JPH033439B2 - - Google Patents

Description

Claim 1: A method for providing a call message service in a telephone system having a memory and handling a plurality of telephones, which method comprises: during a call from a calling telephone to a main telephone;
automatically generating a callback message for the main telephone in response to an activation signal from a telephone handled by the system and having a predetermined relationship to the call; and storing the callback message in the memory. storing and automatically providing a message-waiting indication on the primary telephone to indicate the presence of the stored message, the call-back message containing a telephone number associated with the call and the activation of the call-back message; A method for providing a call message service, which is determined by a predetermined algorithm depending on the telephone that generated the signal.

2. In the method set forth in claim 1, the system is provided with facilities for transferring a call to a specific telephone under predetermined conditions, and the step of generating a callback message is performed when a call is sent from the specific telephone. Type 1 (LWC)
1. A method for providing a call message service, characterized in that the number of the specific telephone is included in a call back message in response to an activation signal of the call message service.

3. A method for providing a call message service according to claim 2, wherein the specific telephone is a call cover telephone.

4. In the method set forth in claim 1, the system is provided with a facility for automatically transferring a call to a call cover telephone under predetermined conditions, and the step of generating a call back message is performed by: A method for providing a call message service, characterized in that the number of a calling telephone is included in a call back message in response to a second type of activation signal from a call message service.

5. In the method according to claim 1, the callback message generating step includes the callback message including the number of the calling telephone in response to an activation signal from the calling telephone. Method of providing call message service.

6. The method according to claim 1, wherein the callback message generation step includes the callback message including the number of the calling telephone in response to an activation signal from the main telephone. How we provide message services.

7. The method of claim 1, further comprising the step of directing the call to the primary telephone in response to receiving an off-hook signal from the calling telephone and subsequent receipt of the primary telephone number; A method for providing a call message service, characterized in that the step generates a call back message in response to reception of an activation signal during any stage of the call.

8. The method of claim 7, further comprising the step of omitting the step of transmitting the call to the destination in response to receiving the activation signal prior to receiving the primary telephone number. How we provide message services.

9. The method of claim 1, further comprising the step of calling the primary telephone in response to receiving an off-hook signal from the calling telephone and subsequent receipt of the primary telephone number, wherein the message generating step is performed on the primary telephone. A method for providing a call message service comprising the step of generating a call back message in response to receiving an activation signal during ringing of the call message service.

10. The method according to claim 9,
A call message service further comprising the step of: ceasing ringing of the main telephone after generating a callback message in response to receiving an activation signal from the calling telephone while the main telephone is ringing; Method.

11. In the method according to claim 1,
The call back message includes the number of the telephone requesting the call from the primary telephone;
A method for providing a call message service, characterized in that the message generation step includes making the calling telephone a telephone that requests a call back in response to receiving an activation signal from the calling telephone.

12. In the method according to claim 1,
The callback message is designed to memorize the number of the telephone that requests a call from the main telephone, and the message generation step is such that, in response to receiving an activation signal from the main telephone, the callback message is sent to the telephone that requests the callback from the calling telephone. A method for providing a call message service characterized by:

13. In the method according to claim 1,
The telephone system has facilities for transferring calls from a primary telephone to a call covering telephone under predetermined conditions, and a callback message stores the number of the telephone requesting the call from the primary telephone; A call message service characterized in that the message generating step sets the covering telephone as the telephone that requested the callback in response to receiving the first type of wake-up signal (LWC) from the covering telephone after the call transfer. How it is provided.

14. In the method according to claim 1,
The telephone system has facilities for transferring calls from a primary telephone to a call covering telephone under predetermined conditions, and a callback message stores the number of the telephone requesting the call from the primary telephone; A method for providing a call message service, characterized in that the message generating step sets the calling telephone as the telephone that requested callback in response to receiving a second type of activation signal from the covering telephone after the call transfer.

15. In the method according to claim 1,
A method for providing a call message service, comprising the step of notifying an initiating telephone that a call back message has been stored.

16. The method of claim 15, wherein the step of notifying includes automatically lighting up a callback lamp on a signal-activated telephone.

17. A method as claimed in claim 15, characterized in that the notification step provides a confirmation tone to the signal-activated telephone.

18. A method according to claim 13 or claim 14, further comprising the step of notifying the covering telephone that the callback message has been stored.

19. A method for providing a call message service according to claim 18, characterized in that the step for notifying includes lighting up a callback lamp of the cover telephone.

20. In the method according to claim 1,
A method for providing a call message service, characterized in that the signal activation telephone is provided with a call back message activation button for generating an activation signal.

21. In the method according to claim 1,
A method for providing a call message service, characterized in that the activation signal is a predetermined dial access code.

22. The method according to claim 1 or 14, including the step of confirming whether the signal-activated telephone is a telephone eligible for generating the call-back message before generating the call-back message. A method of providing a featured call message service.

23. In the method as claimed in claim 22, further comprising, for each telephone handled by the system, an indication (LWC-SND) indicating whether the telephone is eligible to initiate callback generation.
A method for providing a call message service, characterized in that the ASG) is stored and its instructions are checked before the callback occurs.

24. A method according to claim 22, further comprising the step of notifying the activated telephone that if the activated telephone is not eligible, the generation of the callback message is rejected. How we provide our services.

25. In the method according to claim 1,
The method for providing a call message service further comprises the step of removing the call back message from the memory in response to receiving a cancellation signal from the telephone of the number included in the call back message and the main telephone number.

26. The method according to claim 22, further comprising the step of confirming whether the telephone number included in the callback message is permitted to request cancellation of the callback message. A method for providing a call message service.

27. In the method of claim 26, the method further includes: for each telephone handled by the system an indication (MSG-LCK) indicating whether the telephone is eligible to be placed in a locked state;
-ASG) is memorized, the cancellation step further determines whether the telephone whose number is included in the callback message is eligible to be locked, and determines whether the telephone is in the locked state. A method for providing a call message service, comprising the steps of:

28 A call message service device that handles a plurality of telephones in a telephone system, which includes a main processor 107 that controls interconnection of the telephone system, a memory 108, message waiting notification devices 200 and 300 in each of the telephones, and a call message service device that handles a plurality of telephones in a telephone system. First device 207, 310, 30 provided in each phone for activating the service
7,325; the primary processor is responsive to information in memory directing an activation operation of the first device at a telephone associated with a call directed to the called primary telephone 901; a) generating a callback message containing the number of the primary telephone and the number of the associated telephone in response to a request by the initiating telephone; b) storing the callback message; and c) activating a message waiting notification device in the primary telephone. A call message service device, characterized in that the call message service device is configured to operate.

29. A call message device according to claim 28, comprising an application processor 103, a secondary memory 113 associated with the application processor, and data channels 100, 111 that interface the main processor and the application processor. A call message device characterized in that the means for generating a back message includes means (SND-STOR) for transmitting a call back message to the application processor for storage in the secondary memory.

30. The call message device according to claim 28, further comprising a secondary memory (LWC-SND-ASG) for storing an indication of the qualification of the activated telephone that requested generation of the callback message, and the processor A call messaging device characterized in that it verifies the qualifications of a telephone.

31. The call message device according to claim 28, further comprising a secondary memory (LWC-RCV-ASG) for storing an instruction indicating whether the main telephone is eligible to receive a callback message, and is a call message device characterized in that it verifies the qualifications of a primary telephone.

32. The call message device of claim 28, wherein the processor provides confirmation of storage of the callback message to the initiating telephone.

33. The call message device of claim 32, wherein the processor lights a lamp associated with the first device in the activated telephone.

34. The call message device of claim 32, wherein the processor applies a tone signal to the activated telephone.

35. The call message device according to claim 28, wherein the processor cancels the call back message for the primary telephone and the activated telephone in response to receiving the cancellation signal and the primary telephone number from the activated telephone. Features of call message device.

36. The call message device according to claim 35, wherein the cancellation signal is a predetermined dial access code.

37. The call message device according to claim 36, wherein the processor locks the activating telephone in response to a lock signal from the activating telephone, and when the activating telephone is in the locked state, the processor receives a message from the activating telephone when the activating telephone is in the locked state. A call message device characterized in that it rejects cancellation.

38. The call message device according to claim 37, wherein the lock signal is a predetermined Daicel access code.

39. The device according to claim 28 or 35, characterized in that the processor deactivates the notification signal of the main telephone in response to deletion of all call back messages to the main telephone. Device.

TECHNICAL FIELD The present invention relates to a method for providing call message service for a primary telephone in a telephone system having a storage memory and serving a plurality of telephones.

BACKGROUND OF THE INVENTION A call covering device is a device that allows calls to a main telephone to be answered by someone other than the master (the subscriber of the main telephone) for purposes such as receiving messages. Such equipment consisted of a call coverage pool, a main telephone line storage terminal connected to the secretary's telephone, and a call pickup service. Call pickup allows calls directed to a predetermined group of telephones to be answered by any other telephone within the group. Typically, the telephone answering the call pickup group goes off-hook and dials a special access code. The call is automatically transferred to the answering telephone. In the form of a typical bridge storage terminal,
The secretary or handler answers the call to the main telephone by pressing a dedicated button to bridge to the main telephone line. The responding subscriber receives the message for the host and informs the host of the presence of the message by pressing a dedicated button to light up the message waiting lamp on the main telephone.

More recently, automatic callback and e-mail services have emerged to enhance service for telephone subscribers. Automatic callback service is a service that automatically monitors when the other party is busy and requests the system to call both telephones when both are free. E-mail services require sophisticated terminals such as a keyboard on the calling party's telephone and a cathode ray (CRT) display on the called party's telephone. The caller dials a special phone number that connects to an electronic messaging service, then types a text message that can later be read on the destination phone's CRT.

Although e-mail provides an excellent messaging service, it is inherently expensive and therefore available only to a select number of subscribers in many applications. Although automatic callbacks are effective, they are not flexible enough to meet the needs of all users. Manual messaging services of various types, on the other hand, are cumbersome and
It is slow and expensive in terms of labor costs. Therefore, there is a need in telephone technology for a flexible, inexpensive, and convenient messaging service.

According to the invention, this problem is addressed by the telephone being one of the telephones handled by the system during a call from the calling telephone to the main telephone and which has a predetermined relationship to the call. automatically generates a callback message to the main telephone in response to receipt of an activation signal from one of the telephones associated with the call and determined by a predetermined algorithm. The problem is solved by a method that stores a callback message in memory, including a callback number, and automatically displays a message waiting display on the main telephone indicating the existence of the stored message.

SUMMARY OF THE INVENTION The problems described above are solved and the state of the art is advanced in a method for providing call messaging services in a telephone system that handles multiple telephone sets. The system generates a call back message for the called principal telephone in response to an activation signal from one of the telephones associated with the call to the principal telephone. The message contains the telephone number associated with the call and is identified by a predetermined algorithm. The system stores the message in system memory and automatically provides a message waiting display for the primary telephone to inform the primary telephone of the presence of the message.

This call message service is called, for example, a "leave word calling" (LWC) service. The LWC service is an integrated part of an advanced comprehensive message service and call coverage system.
This system generates an automatic call back message for calls to the primary telephone and forwards the call to a predetermined call covering telephone, such as a secretary telephone or message center.

Some of the telephones handled by the system are equipped with an LWC button for activating the generation and storage of LWC messages. For phones without an LWC button, this feature can alternatively be activated by dialing an access code.

The LWC feature can be activated at any time during a call from any telephone associated with the call. For example, such a telephone may be, for example, a calling telephone, a called telephone, or an answering telephone. In each case, a message is stored that requests the calling telephone to return the call. The calling telephone is defined as the answering telephone for which the LWC message is intended when the answering subscriber activates the feature. This allows the answerer to accept a text message other than a simple callback request from the caller to the host, and when the host receives the text message, generates an LWC message to call the answerer. and memorize it.

According to a feature of the invention, a caller on a telephone equipped with an LWC button can generate an LWC message by pressing the LWC button after going off-hook and dialing the number of the main telephone. . For example, if the primary telephone or answering telephone is in a call state when the LWC feature is activated, the call state is not affected. On the other hand, in a call state other than a telephone conversation, the call is terminated by activation of the LWC function.

LWC immediately after receiving the dial tone before receiving the dial tone and dialing the number on the primary phone
By pressing a button, the calling party can activate the LWC function without ringing the main phone. To perform the LWC function from a telephone that does not have an LWC button, the calling party must activate a dial tone by an action such as flashing a switch on the telephone. The calling party receives a dial tone, dials a special access code, and then dials the number of the primary telephone. After the LWC is activated by dialing a special access code, the main phone will not ring.

In the illustrated system disclosed herein, calls may be transferred based on specified conditions such as call pickup or call following. In other conditions, the call may be automatically transferred to the covering phone. The cover phone has
A second button called the “Cover Callback” (CC) button
button can be provided. An LWC message is also generated and stored when the covering subscriber presses the CC button for a call to the primary telephone. However, the LWC message generated by the CC button requests that the host call back the calling subscriber, not the covering subscriber.

Subscribers with LWC and CC buttons also have a confirmation light for each button. After pressing the respective button, the appropriate lamp will illuminate to confirm that the callback message has been correctly stored in memory. For dial access telephones, a special confirmation tone is given to indicate successful message storage. If for some reason the message cannot be stored correctly, a failure signal is given to the initiator.

In one advantageous embodiment, the main processor controls the switching operations of the telephone system. An application processor and disk storage system is provided to alleviate the storage requirements of the main processor. The main processor and application processors communicate with each other through data interface units and channels. The main processor is
Controls the generation and routing of LWC messages. The main processor also controls the lighting of the automatic message waiting (AMW) lamp according to instructions from the application processor to notify the host of the existence of an LWC message.

In order to retrieve LWC messages, the main phone is equipped with a display device with, for example, 40 characters. You can call your secretary, who has a phone with a display on your host's phone, to search for messages. In either case, a search for LWC messages is initiated by actuation of the message search button on the display. This puts the display in search mode. display
By pressing the STEP button, the first (or next) message is displayed. Each message includes the name of the calling party, the date and time of the call, A or P indicating morning or afternoon, respectively, and the number of LWC messages generated from the calling phone to the main phone (this has a predetermined maximum value). ) and the number of the calling telephone. 2 or more times means 2 or more calls from the same caller.
Indicates that an LWC message has occurred, but only the most recent one is actually retrieved.

The displayed message is configured to be automatically stored in the storage device unless deleted or canceled by pressing a DELETE button attached to the display. Even if the next message is stored, it will not be displayed unless you press the STEP button again. If there is no message to display, STEP
By pressing the button, a message indicating "no message" is displayed.

Message Callback From the telephone, the subscriber can cancel LWC messages. This is accomplished by first pressing the LWC CANCEL button or dialing a cancel dial access code while listening to the dial tone on the calling party's telephone. The calling party then designates the primary telephone by dialing the primary telephone number. This results in the appropriate message being deleted, a confirmation tone being given to the calling party, and the state of the AMW lamp changing if necessary on the primary telephone.

Some telephones now have the option of being locked to prevent unauthorized persons from retrieving or canceling LWC messages. To accomplish this, a secret dialing code is used to lock and unlock the phone. When locked, the phone's display set CANCEL button is disabled and the display cannot be put into display mode.

[Brief explanation of the drawing]

In the drawings, FIG. 1 is a block diagram showing an example of a telephone system in a subscriber's premises in a private branch exchange in which the present invention is used. Figures 2 and 3 are
This is an example of a telephone used in the system shown in the figure.
FIGS. 4-8 are layouts of tables of related data used by the program to control the system of FIG. FIGS. 9, 10, and 11 are diagrams symbolically showing a telephone in the state of a main telephone and call coverage routes for each of the main telephones. FIG. 12 is a table of associated software states that define the state of a call during processing in the system. Also shown are the associated stimuli that initiate the call processing activities that are performed on the call for each call processing state and the names of the program routines that are executed as a result of the stimuli. 13 through 21 show flowcharts of program routines that primarily control the transfer of the coverage path of FIG. Figures 22 to 29
The figure is a similar flowchart related to the processing of LWC and CC messages. FIG. 30 is a flowchart of a program used to update the on/off status of the station's automatic message waiting lamp in response to the accumulation of messages on the main telephone. FIG. 31 is a flowchart of a program having the function of locking and unlocking the station to prevent unauthorized retrieval of stored LWC type messages. 32 to 36 are flowcharts of the message search program. FIGS. 37 to 41 are flowcharts of several subroutines called in various cases of the above program structure.

General Description The invention is implemented in this example in a subscriber premise telephone system with extensive call coverage.

A set of call coverage conditions is stored in memory for specifying the conditions for transferring a call to the primary telephone to the covering telephone. A covering telephone is one or more predetermined telephones designated to receive calls to a primary telephone (PS) under call coverage conditions. The number of the first cover phone of the primary phone is stored. Furthermore, the numbers of one or more cover telephones other than that main telephone are stored in order of cover priority. Coverage conditions are checked in response to a call to the primary telephone, and when the conditions are met, the call is
The cover will be forwarded to your phone. If the call is not answered at the first covering telephone for a predetermined period of time, it will be returned to the first covering telephone in the specified priority order until the call is answered from the first covering telephone or the call is abandoned. Transfers are automatically made from to each of the other covered telephones.

Coverage conditions have become more common than known techniques. Importantly, the conditions are now determined by the type of incoming call as well as the state of the primary telephone. Calls to the primary phone may be transferred immediately to the cover phone, may go only to the primary phone, or are first addressed to the primary phone and sent to the cover phone only if the primary phone does not answer within a predetermined period of time. The call may be forwarded to a telephone, all of which are determined by coverage conditions, including selections including call type and primary telephone status, as discussed below.

In traditional telephone systems, a telephone has either one line or multiple lines associated with different selection buttons. In the system disclosed herein, a telephone may have a single line with multiple call appearance appearances, each corresponding to a separate button, or a telephone may have multiple line appearances, each with multiple call appearance appearances. It's okay to have a line. Each call storage terminal may be simultaneously associated with an independent call function. Thus, for example, a telephone may have a line with three call deposits, with a call on hold at one call deposit at any given time and a call on hold at the other telephone deposit. There is a situation where the user is talking to the calling party while the third call storage terminal is experiencing ringing on the incoming call. A telephone line is said to be active if one or more of the call acceptance terminals on the telephone line are associated with a call function. If all call acceptance terminals are active, the telephone line is blocked and active. In the example described herein, the coverage method generally operates in conjunction with a single telephone line. Therefore, in a telephone set having a plurality of lines, different coverage conditions may be specified for each line.
To simplify the method and aid understanding of the invention, the following discussion assumes that each telephone handled by the system is provided with a single line with multiple call acceptance terminals. Although,
It is to be understood that the scope of the claims is not limited thereto.

Based on the above background, let us define in detail an example of cover conditions. Regarding the state of the main telephone, in an advantageous embodiment of the invention the main telephone is activated only when the telephone is active, only when the telephone is busy or only when the telephone is unanswered for a specified time. You can specify that calls be forwarded to a covered telephone. Regarding the type of incoming calls, the main telephone can only accept calls originating from telephones handled by the system (internal calls) or calls originating from telephones not handled by the system (external calls).
You can specify that only the cover will be transferred to the phone. The above call class coverage selections are combined in any manner with telephone state coverage selections. Thus, for example, the primary telephone could, if desired, specify that only external calls directed to the active telephone, or only internal calls directed to the blocked telephone, be forwarded to the cover telephone. Similarly, all calls can be transferred immediately by selecting both all internal call coverage and all external call coverage. Another example may be to specify that external and/or internal calls be forwarded only when the primary telephone is unanswered for a specified period of time. In summary, the primary telephone has complete freedom to specify the desired coverage conditions within the illustrated coverage environment.

There are also types of calls for which call coverage does not apply. As discussed below, one such type of call is from a covered subscriber, such as when a secretary in charge of a covering telephone calls the primary telephone to answer a call covered by the secretary. It is. The master telephone could also route all calls to the cover and have the secretary tell the master to answer the call in question. In order to prevent even calls from the secretary to the master from being routed to the secretary according to the coverage conditions, calls are classified as priority calls. Calls in this class are automatically removed from coverage conditions.

The covering method "All Call Forwarding" (SAC) operates in part like a conventional system. The host performs this function by dialing an access code or by pressing the SAC button on a telephone with a feature button. In either case, all subsequent calls will be made until the feature is deactivated.
Transferred to cover phone. The system disclosed herein is capable of functioning on one or more calls currently incoming to the primary telephone.
Expanding SAC functionality. Therefore, by simply pressing the SAC button on the main phone where the SAC function is not active, an incoming call can be immediately transferred if necessary. This function then remains active until, for example, the button is pressed again. To forward only incoming calls without activating this feature, the host must use SAC twice in a row.
All you have to do is press the button.

Detailed explanation: In the drawings, for 3-digit numbers, the first digit is 4.
Regarding digit numbers, the first and second digits indicate the drawing number in which the corresponding component appears.
Thus, for example, components 305 and 1602 appear in FIGS. 3 and 16, respectively.

FIG. 1 illustrates a digital communication system in which the present invention may be implemented. The system has four main components - control processor 101, switch 102,
It includes an application processor (AP) 103 and a message center (MC) 104. The control processor 101 is a central processing unit (CPU) 10.
7, which may be any of the many types of processors commercially available, which use instructions and data stored in memory 108 to control the major operations of the system. Specifically, the CPU 107 controls the operation of the switch 102 via the channel 114. Additionally, the control processor 101 communicates with the AP 1 through data connections including a digital channel interface unit (DCIU) 110 and a digital data channel 111.
Communicate with 03.

Switch 102 is connected to a time-division network 106 that provides time slot interconnections between telephone extensions such as 100-1 to 100N and between the telephone extensions and a trunk 109 to a switching office (not shown).
A digital exchange network that includes Each extension telephone and trunk is connected to network 106 via interface port circuits 105 and 116. CPU107 is connection 1
14 and an input/output interface circuit 115 to communicate with the telephone and trunk by three port circuits.

DCI 110 is connected to CPU 107 and AP 103 via a data access channel.
AP103 has its own central processing unit AP/
It includes a CPU 112, which can be implemented with a commercially available microprocessor. AP 103 also includes mass memory 113 for managing functions that handle large amounts of data, such as leave word calls (LWC), and message center 104 management. For example, LWC messages are stored in mass memory 113 and retrieved. The PCIU interface program will not be described in detail, but it controls the transmission and reception of data with the AP. Large capacity memory 113
can be achieved by any number of commercially available systems.

Message Center MC 104 is used in this example as the final coverage point for calls directed to the primary telephone. A detailed understanding of MC is not necessary for understanding the present invention and will only be described in general terms. A system may have multiple MCs; only one is shown here for simplicity. MC handler position is 10
It includes a telephone such as 0-N, a display terminal, and a keyboard 117. Although only one of these positions is shown in Figure 1,
The MC may contain several handler positions.
MC's phones are accessed as part of a Uniform Call Distribution (UCD) group. Assume that a call destined for the main telephone is transferred to MC 104 for cover service and arrives at a telephone such as 100-N. At the same time, the CPU 107 notifies the AP 103 of the cover call of the telephone 100-N, the main telephone that is the original destination of the call, and the reason for the call transfer. In response, AP 103 accesses a large-capacity memory file related to the primary phone and displays information on terminal 117. This displayed information includes, in the illustrated example, the terminal number, the reason for forwarding the subscriber's name call at the principal telephone to the secretary, and any text information that the principal has placed in the data file. The text information may include, for example, the host's whereabouts, return, messages for a particular caller, etc. The displayed information at terminal 117 also includes calling party number information.

The displayed information allows the MC handler to respond intelligently to calls as if the handler were the host's secretary. The operator is terminal 11
7, the message from the calling party can be directly input into the data file of the host.

FIG. 2 shows a typical multifunction telephone that can be used as a primary telephone. The telephones used in the illustrated system may be analog or digital. Features such as Leave Word Call (LWC) and Transfer All Calls (SAC) can be activated from either analog or digital telephones. Multifunction telephones are provided with function activation buttons. However, the feature can be activated from any phone with a Dial Access Code (DAC).
The telephone of FIG. 2 has three call terminal selection buttons 201-203 associated with the single line telephone number 4388. Although independent calls can exist on each of these call storage terminals at the same time, only one of the calls can be in a talking state. The lamp 208 associated with each call storage terminal is called an I-use lamp and indicates the state of the call storage terminal selected by operating the associated selection button. The lamp 209 is a status lamp, which lights up steadily, flashes and causes ringing,
Displays the status of the call storage terminal, such as in progress or on hold.

Generally, most of the buttons on the telephone of FIG. 2 are assigned as call storage terminal buttons or special function buttons, as desired. In the illustrated example, the telephone has activation buttons assigned to the SAC and LWC functions, respectively. When the SAC function is activated by actuating button 206, all calls, future calls as well as currently incoming calls, coming to that telephone are stored in the system in relation to this system. It is forwarded to the cover phone according to the cover information. Second time press SAC button 206
The SAC function is canceled by pressing .
LWC button 207 activates the LWC function. I-
Youth lamps are not used as these function buttons. Status light 2 related to SAC button
04 lights up constantly when this function is activated. When the LWC message is successfully generated and stored, the LWC status lamp 20 is activated in response.
5 lights up during a call. Lamp 205 is turned off at the end of the call. This light flashes when an LWC attempt is unsuccessful or invalid.

If the LWC message is successfully generated and stored for the master associated with the telephone in Figure 2,
The host is informed of the message by lighting up the AMW lamp 200 located on the left hand button in Figure 2. As an example, suppose this phone does not have a message retrieval display. To search for messages, the master must call his secretary with a display, if one exists, or call the MC.

Figure 3 shows a typical telephone used by a secretary. This has essentially the same function as the set of FIG. Additionally, this phone has some features specific to secretaries.

One such feature is a 40-character alphanumeric display that is used to search LWC and CC messages, and to retrieve MC messages that also fit into a 40-character display. This display module may be attached to the phone, or the phone may be independent. Messages to the owner of the phone (for example, a secretary) can be sent using the Message/Search Mode (MRM) button 30.
It can be obtained by manipulating 6. If the telephone is in the coverage path of one or more principal telephones, messages for those principal telephones may be obtained by pressing the Cover Message Retrieval Mode (CMRM) button 307. After the message is displayed, the message is deleted from storage by pressing the delete button 308. Otherwise, the message is left for later retrieval. By pressing step button 309, the next message will be displayed; if not, it will be displayed that there are no more messages.

In addition to the LWC and SAC buttons, the telephone of FIG. 3 includes a cover callback (CC) button 310 and a meeting button 311. Both buttons operate only for calls covered by the telephone. A LWC type message is generated and stored by the CC button. In the case of actuation of the LWC button on the cover telephone, a request is made to the main telephone to call the calling party rather than the cover subscriber.

The meeting button allows the covered subscriber to establish a preferential connection to the primary telephone to which the covered call is directed. To implement this function, the covered subscriber first presses the transfer button 312 or the meeting button 313 to put the covered call on hold. This action causes the system to select an empty call storage terminal. Actuation of the meeting button automatically places the call at the selected call receiving terminal on the primary telephone. Since the meeting call has a priority status, no transfer is performed for call coverage.
The next press of the conference or transfer button will connect the calling telephone, cover telephone and main telephone, or calling telephone and main telephone, respectively.

Any button other than a dedicated button such as button 314 on the cover phone may be used for automatic message waiting (AMW) for the primary phone. In such a case, the button will have no function and the associated lamp, such as 215, will light up corresponding to the AMW lamp of the main phone.

Table Descriptions Figures 4 and 8 show tables of data used by system programs when processing calls. The terms "telephone" and "telephone line" are used herein because of the simplifying assumption that the telephones in the system have one line that can have multiple call receiving terminals. They can be used interchangeably. FIG. 4 is a parameter table defining system parameters defined by the system customer. A given telephone line in the system for which coverage has been defined is assigned to a call coverage group (CCG). Customers may define any number of call coverage groups. Table LXLN6 contains a storage word for each call entry in the system that defines the covered services applicable to that call entry. Call receiving terminals are classified by extension line numbers (ILNs) that can be assigned arbitrarily. Therefore, telephone 9
01 (FIG. 9) is assigned to ILN0, which refers to the first word of LXLN6 and is assigned to CCG0. Each word of LXLN6 associated with a call deposit on the same telephone line has the same CCG number contained within it.
Each word of LXLN6 has a display device.
Contains a flag COV _- RET _- ALLOW indicating whether a cover phone for its master phone in the CCG is allowed to retrieve its master's LWC messages.

The second table LXLN contains words for each ILN. Each word contains a class of service indication CLSRV for that primary phone.
CLSRV contains numbers that define the features applicable to that line. CLSRV is used as an index to address the line service class table LCOST4, which defines certain features for that line. The functions relevant to this specification are LCOST4
is shown. Specifically, the flag
SNDALL indicates whether the SAC function can be activated for the given line. flag
LWC _- SND _- ASG indicates whether the LWC function can be activated from that line. Flag LWC−RCV
-ASG indicates whether the line may memorize LWC messages about the line as a master.

As a cover table, there are 4 COVRTBL0 to
COVRTBL3 is shown. Each has LXLN6
The CCG number obtained from is used as an index. COVRTBL0 contains call coverage conditions applicable to telephones assigned to applicable CCGs. Each group in the table contains two groups of conditions. The first group CVR-INT indicates conditions applicable to extension calls (calls from telephones handled by the system). Within this group, the CDA-INT flag means to cover extension calls when the primary telephone is not answered, CBSY _- INT means to cover extension calls when the telephone is busy,
CACT-INT means to cover extension calls when the phone is in operation; CALL _- INT means to cover all extension calls. The second group, CVR _- EXT, contains flags corresponding to the above-mentioned internal calls, which relate to external calls to the main telephone (calls from telephones not handled by the system).

Additionally, each word of COXRTBL0 is CVRPTS
The number of covered telephones defined for each CCG in PRINC _- DA _- INTV Transfers calls to the covered telephone when the covered primary telephone is not answered (D/A) (external or internal). The length of non-response time counted in 2-second intervals is memorized.

COVRTBL1 contains information about the first covering phone for each of the CCGs. flag
GRPFLG1 contains 1 if the first covered phone is in the Message Center (MC);
Contains 0 if the cover phone is an individual phone.

Furthermore, each word of COVRTBL1 contains the display CVR _- PT1 containing the ILN of the first covering telephone or, if part of the MC, such as covering telephone 104, the MC number. If no CCG cover phone has been determined, CVR _- PT1 contains 0.

COVRTBL2 and COVRTBL3 contain the same information as COVRTBL1 about the second and third covering telephones, if any, in each CCG.

As described below, before forwarding a call to a covering telephone, the calling party is informed of this and the calling party is given an option to take an action, e.g., leaving an LWC message, instead of going to the covering telephone. A time period called caller response time (CRI) is given. The number of 2 second time spans selected as CRI by the customer is stored in table CLR _- RST.

Once a call is transferred to a covering station, the call rings for a predetermined period of time at the covering station and then is transferred to the next covering station (if any). The number of 2 second time spans forming this time is stored in table CVRPTDA.

FIG. 5 shows a number of tables, collectively referred to as trunk tables. Each trunk table is indexed by extension trunk number (ITN). The collection of words from each trunk table for a given ITN forms a trunk record. Every call in the system is associated with an individual trunk record. Only the items of interest in this specification are illustrated in the trunk table.

The trunk table TRKTBL1 contains an indicator PM1 (call processing status mark) containing encoded information defining the current call processing status of the associated call in the system.
The associated call processing states are illustrated in FIG.

TRKTBL3 contains the priority flag TOLL _- BIT. If it is desired to prevent the possibility of calls being forwarded to that call covering phone, select TOLL _- BIT
A call is marked as a priority call by setting . Such calls include meeting calls from a cover telephone to a principal telephone during a cover call to the principal telephone. In such a case, the meeting call should not be transferred to the covering telephone, even if the primary telephone's coverage conditions happen to be satisfied.

TRKTBL4 includes a flag TL1 indicating whether the call is an internal call or an external call. For extension calls, item TAC1 of TRKTBL4 contains the ILN of the calling extension. Similar information is available for outside calls.
Given to FAC1.

TRKTBL6B contains the item PRINCIPAL which stores the ILN of the phone called as the main phone. If the call has been transferred to a covering telephone, the field RFDIR _- REASON will contain encoded information specifying the covering conditions indicating what the conditions were that caused the transfer.

TRKTBL6C contains the field REDIR _- TYPE, which contains 0 if the call has not yet been transferred;
Otherwise, a number is included to indicate whether other call services such as call forwarding or call pickup occurred on the call. moreover
TRKTBL6C contains in CVRPT _- NUM the sequence numbers of the first, second, and third coverage points of the current coverage telephone that apply to the call.

TRKTBL7 is the dialed digit D1 of the called telephone number
Contains D4 to D4.

FIG. 6 includes a line status table LSTWD1 indexed by ILN. Each word is a SAC
Set to 1 when the function is activated
Contains the SAC _- STAT flag. In addition, each word contains the item TRKNUM, which is the trunk table entry for the call associated with a given phone.
Remembers ITN index.

If the SAC function is activated on the phone,
All calls then ringing on the telephone are automatically transferred to the covering telephone.
There may be several phones that require call forwarding due to SAC activation during the same period. Due to real-time considerations in the system, each such call is routed sequentially to minimize the amount of time the system can fill in real-time. This is partially true for each call to be transferred from any phone.
This is achieved by generating SAC stimulation.
Each stimulus is stored in a separate word of the table SAC _- QUE, and each stimulus is processed as a separate call process.
The start and end of active addresses requesting SAC _- QUE processing are obtained from tables SAC-QPTR and NUM-SAC.

The remaining tables in Figure 6 primarily contain information regarding LWC functionality. EKT−STA is flag LWC−
Contains ACT-ON, which is set when the LWC message is successfully stored for the primary phone. If LWC is activated as a result of operating the cover callback (CC) button on the cover phone, the flag CVCB-ACT-ON is instead activated.
is set. EKT−STA2 is flag MSG−
Contains LCK-ASG, which is set when the phone is in the locked state. EKT-STA2 also contains item CXF-LN, which stores the number of selection buttons that are reserved in response to activation of the meeting button on the cover phone. This field is used to identify the primary telephone of a covered call for use in the implicit primary telephone address. Furthermore, when an extension call is made from a multifunction telephone, the dialed telephone number is normally stored in the item LAST-NUM. Table DSP-ST0 MSG-UNLCKD
is 0 when the corresponding phone is locked, thereby preventing messages from being retrieved or deleted from the phone until it is unlocked. These tables are identified by telephone index number, which identifies the telephone. On the other hand, the call storage terminal of the telephone is
Identified by ILN.

FIG. 7 shows LWC,
Figure 3 illustrates a table used to transfer information related to CC and MC. Message sending table
SND-XCTB contains the item SND-XCT-TYPE, which is adapted to describe the type of information sent to the AP. There are four types of transmission here. 1) Sent to be stored in AP
2) a request to cancel the LWC or CC message for the specified calling and primary telephone; 3) a request to retrieve the LWC or CC message; or 4) a request to delete the message. If there is a cancellation request, the message is deleted before the primary phone retrieves it. A deletion request removes the message after the display. When LWC and CC messages are accumulated, deleted, or canceled, the item
SND-XCT-EXT contains the telephone number of the telephone requesting a callback from the main telephone;
SND-XCT-BUF will contain the telephone number of the primary telephone. Since LWC and CC messages are predetermined types of callback request messages, the text of the message is not sent to the AP. SND− for message search requests
Main phone (or request phone) with XCT-EXT
You only need to identify.

The message reception table RCV-XCTB is used to send LWC or CC messages, and in some cases MC messages from the AP to the control processor for display on the appropriate main display module. This table is also used to transmit automatic message waiting lamp update information to the primary telephone. Item RCV−XCT−
TYPE contains encoded information that identifies whether a given transmission includes a message, whether the included message is the last message for that phone, or whether there is no message. The main phone is an item
Identified by RCV-XCT-EXT. RCV−XCT
-TYPE also identifies message waiting update information. In this case, the item RCV-XCT-STAT is used to turn on/off the message waiting lamp of the main phone.
Contains an off state. RCV−XCT−
The information encoded in MSGTYPE identifies whether the information is an LWC/CC message or an MC message. Any message text, such as a message from an MC, is RCV−XCT−
Stored in BUF.

A given telephone has up to three receptacles for its Automatic Message Waiting (AMW) lamp.
This allows the main phone to have one AMW lamp and up to two other phones to have AWM lamps for the main phone. The AMW lamp on a feature phone is updated by sending a direct control signal to the phone.
There is also provision for phones without a multi-function button to be installed with the AMW lamp. In this case, the AMW lamp is controlled from an associated telephone line circuit with wiring to the lamp.

The table of FIG. 8 is used to automatically update all message waiting lamp receptacles on the telephone.
The AMWPTRS table is indexed by the phone's ILN in response to lamp update information from the AP to retrieve its entry LAMPTR.
LAMPTR table AMW-APP1 for main phone
and points to the appropriate position of AMW-APP2. These tables can have 1, 2 or 3 words per phone, corresponding to the number of AMW lamp receptacles in the main phone. This is table AMW−APP1 and
Illustrated by Content 1 of AMW-APP2,
Three lamp housing terminals shall have three words, and a single lamp housing terminal shall have three words.
It is indicated by the content R with a single word.
A single lamp housing terminal appears on many instances of that main phone. Items in Table AMW-APP2
LAST-APP is the flag of the last entry in the table associated with any given telephone line.
The item AMW-STA-NUM in table AMW-APP1 contains the telephone number of the multifunction button telephone and flags of other telephones. If AMW-STA-NUM indicates a feature phone, AMW-BTN-
The ID contains the AMW lamp number by which the lamp can be controlled. Otherwise, the AMW-BTN-ID contains the ILN of the non-feature telephone by which the appropriate line circuit to control the AMW lamp is addressed.

Program Description FIGS. 9-11 show 901, 902, 100, shown here as being in the main telephone state.
An example of 1,1002 telephones 100 and the assignment of call coverage groups (CCGs) for these primary telephones is shown. These assumed assignments are used here as an example to explain the operation of the system. In FIG. 9, telephone 901 is CCG0
is assigned to. CCG0 is the first,
Telephone 90 as second and third cover telephone
2,903 and MC104.

Telephones 1001 and 1002 are assigned to CCG1 as shown in FIG. CCG1 consists of only two cover phones. The first cover phone is phone 902, which is also the first cover phone of CCG0.
It has become a cover point. CCG1's second cover phone is MC104.

Telephone 902 is the cover telephone for CCG0 and 1, but it qualifies as the primary telephone like all telephones in the illustrated system.
FIG. 11 shows that telephone 902 is assigned to CCG2, which means that it has only MC 104 as a coverage point.

According to the cover configuration assumed above, phones 901, 1001 and 1002, if available,
is primarily covered by telephone 902. If 902 is unavailable, calls to telephone 902 are then covered by telephone 903 and finally by MC 104. telephone 10
Calls to 01 and 1002 are secondly covered by MC 104 if telephone 902 is unavailable. Calls with telephone 902 as the main telephone are covered by MC 104.

The data shown in call cover table LXLN6 and COVRTBL1 to COVRTBL3 in FIG. 4 show the above-described cover configuration for CCG0, 1 and 2. Further, as shown in table COVRTBL0, for purposes of explanation it is assumed that all internal and external calls to the main telephone of CCG0 are covered immediately (CALL-INT, CALL-EXT). All external calls to phones in CCG1 are covered when the phone is blocked or unanswered; internal calls are covered when the phone is blocked (CBSY-EXY, CBSY-INT , CDA−EXT).
CCG2 telephones only cover external calls when the telephone is active and unanswered, and cover internal calls only when blocked.

Call Cover (Deputy Reception) For illustrative purposes, telephone 9 from telephone 1001
Consider an extension call to 01. FIG. 9 shows a telephone 90
1 has a cover path consisting of telephones 902, 903 and MC 104. telephone 9
Recall that all internal and external calls on 01 are eligible for immediate coverage. Assume that the operator is not present at the cover telephone 902 and the SAC function is operating on the cover telephone 903.

FIG. 13 shows a program (CPRTN63) that is entered when the number of telephone 901 is dialed from telephone 1001. The dialed telephone number is translated into the internal line number (ILN) of the primary telephone 901 at step 1302. CPRTN 63 then calls the CVR-CHK subroutine at step 1303 to determine whether any coverage conditions are initially satisfied.

The subroutine CVR-CHK is shown in Figures 37 and 38.
As shown in FIG. 39 and FIG. 39, if the cover condition checked by the subroutine is not satisfied, 0 is returned. If one coverage condition is satisfied, CVR-CHK returns 1. In determination 3702, it is determined from the item REDIR-TYPE of trunk record TRKTBL6C whether the current call was previously transferred to the cover. If so, CVR−
CHK returns 0 to the startup program. If the call in this example has not yet been forwarded, the subroutine proceeds to decision 3704, which determines from bit TOLL-BIT in table TRKTBL3 whether the call is a priority call. If so, 0 is returned. Recall that priority calls are calls for which cover service is not allowed, such as meeting calls. The call in this example is not such a call, so
At decision 3706, the subroutine determines whether conventional call following is active. Such a check is performed because, in the preferred embodiment, conventional call forwarding takes precedence over call coverage. Since it is assumed that call following is not active on telephone 901, decision 3708
In , the subroutine CVR-CHK is
Bit SAC-STAT (FIG. 6) in LSTWD1 is checked to determine if SAC is active on telephone 901.

If SAC is active, step 3
709 sets REDIR-TYPE to indicate that the call was forwarded for cover (not for call following, etc.) and step 3710
Set REDIR-REASON to SND-ALL with
CVR-CHK returns a 1 to the initiator, indicating that all calls to that phone will be forwarded. Since the SAC is not active on telephone 901, the appropriate call coverage group (CCG) is retrieved from table LXLN6 (FIG. 4).

If the primary telephone does not have a primary telephone assigned to it, a zero is returned to the startup program in step 3713. Since telephone 901 is assigned to CCG0, judgment 3715
TL1 of TRKTBL4 is timed to determine whether the call is from an outside line.

Since this call is an extension call, the program advances to step 3801 in FIG. If the call was an external call, the program proceeds to step 3901 of Figure 39, where the coverage conditions for the external call are tested.

Judgment 3801 in Figure 38 is COVRTBL0 (4th
Read the 4-bit item CVR-INT in Figure). If the value of the item is 0, there is no extension call coverage condition, and the CVR-
CHK becomes 0. Step 3801 determines that an extension call coverage condition exists. In FIG. 38, internal conditions other than the "no response" condition are tested individually. In this example, by determination 3803
It is determined that CALL-INT is set, indicating that all extension calls to telephone 901 should be covered. Step 3804 therefore sets the REDIR-TYPE of the call cover and
Step 3805 connects CVR-CHK to terminal 3806
Cover all calls before sending one back to
Set REDIR-REASON.

Under other conditions, subroutine CVR-CHK performs other tests for extension call coverage conditions. If CALL-INT is not set, bit CACT-INT is evaluated in decision 3807 to determine whether to cover when the primary telephone is active on one or more call acceptance terminals. If so,
In step 3808, it is determined whether all call storage terminals are free. bit CBST−
INT is checked in decision 3813 to determine whether extension calls are covered when the main telephone is blocked (all call storage terminals active). For each such test, if the coverage condition is satisfied, REDIR-TYPE is set to indicate call coverage and set to reflect the condition that was satisfied.
REDIR-REASON is set.

Calls from outside the system (external calls) are evaluated by the CVR-CHK branch shown in FIG. This branch is essentially equivalent to the branch described above with respect to FIG. 38, except that the external call conditions in item CVR-EXT of FIG. 4 are examined. Therefore, the third
The steps in FIG. 9 will not be described in detail.

In the call described in this example, the subroutine
CVR-CHK gives 1 from terminal 3806 to the program shown in FIG. CVR-CHK also returns the CCG number 0 assigned to main phone 901.
Judgment 1304 learns from return 1 that the conditions for immediate covering are satisfied, and passes control of the program to CV-STA1.

CV-STA1 first executes subroutine FND-CVPT (shown in FIG. 41) in step 1402, and searches for an available cover telephone for telephone 901, if any.

Referring to Figure 41, FND-CVPT first covers cover tables COVRTBL1, COVRTBL2 and
A loop is set up in step 4103 to sequentially test COVRTBL3 to check for available cover phones. Step 4106 selects cover table COVRTBL1, 2 or 3 (fourth
Read the appropriate word determined by one CCG number (see figure). First, the first of COVRTBL1
The cover phone assigned to is examined. The group flag GRPFLG1 of the read word is first examined in decision 4107 to see if the covering telephone is a message center. Telephone 901
The first cover phone is not in the message center. Subroutine FND-CVPT therefore makes three checks to see if a telephone is available to cover the call to the principal telephone. If the covering telephone has call following or SAC is set (Decision 410
8,4109) or the telephone (4110), it is considered that the telephone cannot be used, and FND-CVPT repeats the loop of checking the status of the next covered telephone. In this example, assume that cover telephone 902 is temporarily unattended. However, the SAC function is disabled on this covered phone. Therefore, the program assumes that telephone 902 is available and returns in step 4110 to step 1403 of the startup program to provide the number of the vacant call terminal on telephone 902.

CV-STA1 goes from judgment 1403 to step 14
08, which displays the primary subscriber's name and cover display on the display module (if present) of the originating telephone 1001.

Since the cover phone 902 is not in the message center, step 1409 is replaced by step 1413.
starts execution, where a free call storage terminal on telephone 902 is captured and the associated lamp is lit. However, a call to cover telephone 902 is preceded by a caller response time (CRI), which is explained below.
It will not start until the end. Subroutine DSP
-TERM (1414) (not shown in detail) is called one after another and tells the calling party the name of the primary subscriber and the reason for the transfer retrieved from REDIR-REASON, if any, on the cover telephone 902. Display on display module. At this point in the process, step 1415 provides a forwarding feedback tone (RFT) to the calling party to inform the calling party at telephone 1001 that the call is being forwarded. Step 1416 sets the timing of the RFT. Also at this point, the PM1 entry in the trunk record for this call should include COV-REDIRECT-
FEEDBACK - Sets the SINGLE state. next
Enter the main program to wait for the RFT period to time out.

COV−REDIRECT−FEEDBACK−SINGLE
If the condition exists and the transfer feedback sound times out, the routine CV- in Figure 15 is executed.
CRF1 is called.

The first step (1502) of CV-CRF1 is
Remove RFT. Step 1503 starts another time measurement and calculates the calling party's response time (CRI).
Measure. The length of CRI is stored as a number (2 seconds long) in table CLR-RSP of FIG. This time gives the caller leeway to take action if he does not wish to speak to the coverer. For example, the calling party may abandon the call. The calling party sends a CRI so that the call can be covered by telephone 902.
You can wait. The caller also launches the LWC and
(This will be discussed later.) This may automatically leave a message on the main phone.
CRI starts by excluding RFT,
The CALLER-RESP-INTV-SINGLE state is set by step 1504 and the CV-CRF1
will return to the main program.

In this example, suppose the calling party waits for a CRI to get the call covered. When the calling party's response time times out, CALLER−
In response to the RESP-INTV-SINGLE state, the main program enters CV-CRI1 (first
(See Figure 5).

Step 1506 of CV-CRI1 initiates linking of cover telephone 902. In this regard, step 1507 sets the length of time that telephone 902 will ring before forwarding the call further, if a next covering telephone exists. The amount of time allowed for a first cover phone before the program begins checking for other cover phones is shown as a number of two second time units in table CVRRPTDA shown in FIG. Step 15
08 is COV-USER-DA-ICON- to PM1
Setting the RING state, CV-CRI1 exits to the main program until the covering telephone answers or times out. The possible states resulting from setting this state are shown in FIG. Since it is assumed that there is no operator at cover telephone 902, when the D/A timer expires (state COV-USR-DA-ICOM-RING is set), FIG. As shown in FIG. 17, the routine CV-SACIA shown in FIG. 17 is entered.

CV-SACIA first enters the 41st step in step 1704.
Execute the subroutine FND-CVPT shown in the figure.
FND-CVPT continues the loop set up earlier to find the next covering phone. This is shown in Figure 9 and the items in table COVRTBL2 regarding CCG0.
This is a telephone 903 designated CVR-PT2. This is found in step 4109, but cover phone 903 has SAC active as assumed, and decision 4109 indicates that FND
-CVPT is displayed to find other covered phones.
I will check COVRTBL3.
As seen in COVRTBL3, the final cover phone for CCG0 is MC104, so FND-CVPT
is the routine CV-SACIA (first
2 is returned to step 1705 in Figure 7). This returned 2 indicates that a cover point exists and the cover telephone is at the message center. Since the cover telephone (104) is at the message center 104 (decision 1706), step 1707 stops the call to the last cover telephone 902, and step 1708 places the call in the message center queue (not shown). can be placed in Finally, return to the main program.
The queue is a conventional uniform call distribution queue. The call is routed by the system program to the next available telephone after MC 104, which is the final covering telephone. Details regarding MC call routing and its operation will not be discussed here, but are not necessary for an understanding of the invention.

If the next covered telephone in step 1706 is an individual telephone, subroutine DSP-
TERM (not shown) is called in step 1710 to display the satisfied primary phone coverage conditions on the next cover phone display. Step 17
At 11, the call is transferred to a free call storage terminal on the cover telephone. The call to the previous covering telephone is dropped at step 1712. The D/A timing for the call transferred to the next covering station is set at step 1713. The call status is set to COV-USER- in step 1714 before proceeding to the main program.
Set to DA−ICOM−RING.

D/A Cover Assuming that an outside call is made to telephone 902, consider the operation of the system when the primary telephone selects the D/A cover condition. Although telephone 902 is a cover telephone for a principal telephone as shown in FIGS. 9 and 10, in this example telephone 902 is referred to in the capacity of a principal telephone as shown in FIG. Referring to table LXLN6 in FIG. 4, telephone 902 is assigned to CCG2. In table CVRTBL0, it can be seen that the telephone set in CCG2 has D/A cover for external calls (CDA-EXT=1). As before, the call is first
Enter CPRTN63 in Figure 3. Assuming that the cover conditions such as SAC that result in direct transfer to cover are not initially satisfied, step 1
When the subroutine CVR-CHK returns in step 303, step 1307 is executed, where the telephone 902
It is determined whether or not there is a blockage. If so, a busy tone is sent back to the calling party in the normal manner. Let us assume that telephone 902 is not blocked. If a display set exists, step 1
Appropriate information is displayed on the called telephone at 309, and subroutine CVDA-CHK of FIG. 40 is executed at step 1310 to determine whether D/A coverage applies to this call. Referring to FIG. 40, since this call was not forwarded earlier and is not a priority call, the telephone 9
Assuming call forwarding is not active at 02, step 4008 is executed to determine whether the call came from an outside line or an extension. Since the call is coming from an outside line, step 401
3 checks the external D/A cover flag (CDA-EXT) in table COVRTBL0. Since this flag is set, REDIR-REASON is set to D/A and the program that called it is returned to at 4016. Step 1 like this
Returning to step 311, step 1312 is then executed, where the D/A timing period is set.
The length of this period is PRINC−DA in table COVRTBL0
- taken from INTV, which indicates the length of time, in 2 second time units, to ring the primary phone before initiating a transfer to the cover phone. At step 1313, the call status is PRINC-DA-ICOM-
RING and returns to the main program with the telephone 902 called.

When the D/A timing time ends, the 12th
As shown in the figure, it enters CV-STA2A in FIG. 18. At CV-STA2A, the program begins forwarding the call to the respective coverage path for CCG2. The next covering phone, if present, is found in steps 1804 and 1805. If no covering telephone exists, ringing at the primary telephone continues and the call state changes to ICOM-
It becomes RING.

Subroutine DSP-ORIG (not shown) appends the word "Cover" to the display of the calling telephone in step 1807 if the calling telephone has a display and a covering telephone is available. At step 1808, the call is removed from the primary telephone. If the covering telephone is a separate telephone, the free call terminal on that telephone is captured and the associated lamp is illuminated in step 1810. At step 1812, the called telephone name and host name are displayed on the cover telephone. Next, preparations are made to start CRI. In step 1814, the calling telephone terminates the call, and in step 18
RFT is given at 16. The timing for measuring the length of RFT is set in step 1817. Before exiting to the main program, in step 1808 the call status is set to COV-REDIRECT-FEEDBACK-SINGLE.
is set to When the RFT timing is finished,
CV-CRFI of FIG. 15 is entered and program operation continues as described above.

If the next covering phone is MC, as determined in step 1809, step 181
RFT was launched on 1,1813 and 1815,
At step 1819, the call state is set to the appropriate state for transfer. In this case, upon expiration of the RFT associated with the transfer of the MC, the appropriate program action is performed. These operations are not necessary for understanding the present invention and will not be further described.

All Call Forwarding (SAC) To explain the SAC feature, assume that a call is placed from calling telephone 901 to telephone 1001. Telephone 1001 is idle, but the host is in a meeting. Telephone 1001 begins to ring, but the owner presses the SAC button to process the call without responding. The call is transferred to the covering telephone where it is answered.

Routine CPRTN63 of FIG. 13 is executed as before for the original call. CVR-CHK (37th
Figure 3) examines the cover condition of immediate forwarding, but phone 1 assigned to CCG1
For 001, there is no direct condition that is satisfied. In determination 1307, it is determined that main telephone 1001 has an empty call storage terminal. Since there is an empty storage terminal in the telephone 1001, step 1309 is performed.
The calling party is shown on the display of the main telephone 1001 (if present), and the main telephone is shown on the display of the calling telephone. The subroutine CVDA-CHK in FIG. 40 is called and the telephone 1001
It is determined whether the D/A cover has a D/A cover. For CVDA-CHK, table COVRTBL0 (Figure 4)
bit CDA-INT is tested. FIG. 4 shows that telephone 1001 does not have a D/A cover for extension calls, so terminal 40
Routine CVDA-CHK is routine at 10
Return 0 to CPRTN63. As a result, in step 1315, the state of ICOM-RING is set in the calling program and the main program is entered. As shown in Figure 12, the main telephone is
Called in ICOM-RING state. telephone 10
01's master attempts to eliminate the call by pressing the SAC button.

When the SAC button is pressed, CV−SAC8
(Figure 19). This is the booted phone
Updates the SAC memory state and begins generating SAC stimuli for all calls ringing on the initiating phone. The routine displays all call acceptance terminals of the initiating telephone depending on the previous SAC state.
Operates to set or clear SAC-STAT in LSTWD1 (Figure 4). If SAC is activated on any call storage terminal (SAC−
STAT=1), CV-SAC8 clears SAC-STAT of all call storage terminals. Otherwise,
The program is SAC-STAT for all storage terminals.
Set.

In response to SAC operation on telephone 1001
CV-SAC8 connects telephone 100 in step 1902.
1. Determine whether SAC is active on any of the call storage terminals. If none are, step 1904 prepares a program to activate the SAC state for each call acceptance terminal, otherwise step 190
3 occurs and inactivation is performed. Step 1905
finds the next (or first) call entry to be updated and step 1906 selects the appropriate SAC.
−Update flags in STAT. In decision 1907, it is determined whether the call storage terminal that has just been updated is ringing. This is phone 1001
Assuming that it is the call receiving terminal where the call came in, step 1908 determines whether the SAC is activated. Here, we assume that SAC is activated, so step 190
9 to generate the SAC stimulus, the table SAC-QUE
(Figure 6) shows the ILN of the call storage terminal of telephone 1001.
Put in. Decision 1910 repeats the update process for each remaining call entry. In step 1911, for this example, telephone 100
SAC lamp 1 lights up.

Every few milliseconds, it manages the ILN entries in the SAC-QUE table, and for each ILN entry
SAC- in Figure 20 to generate SAC stimulation
The TASK routine runs. After the ILN of telephone 1001 is stored in GAC-QUE by CV-SAC8, the next time SAC-TASK is entered,
Steps 2002 and 2004 generate SAC call processing stimuli for incoming calls on telephone 1001, and wait step 20 before exiting to the main program.
Clear ILN from 05. SAC stimulation is the 12th
This produces the next entry in CV-SAC3 (see Figure 13) as shown. CV-SAC3 first determines in step 1318 whether the SAC stimulus is from the primary telephone 1001 or was inadvertently provided by the calling telephone. If it is from the calling phone, this is ignored. Because the primary phone has pressed the SAC button, the call is not a priority call (decision 1319 ignores the stimulus in this case), and the call has not yet been transferred to the covering phone (step 1320 Activated SAC is redundant), routine CV-STA2A is entered in FIG. 18 in response to the stimulus.
CV-STA2A transfers the call to the covering telephone in the same manner as described above.

After the CRI times out, the call is transferred to the first covering telephone 902, if the first is available.

It is also possible to activate the SAC feature on the covering phone during the All Call Forwarding CRI period during the caller's response time. By seizing a free call repository before a CRI is initiated, the covering telephone can learn about scheduled call transfers. During this time, wake up
It is in the CALLER-RESP-INTV-SINGLE state. As shown in Fig. 12, when SAC stimulation is received in this state, the program shown in Fig. 15
It will be entered into CV-SAC2. Calling telephone 10
It is also possible that the SAC is inadvertently activated by 01. Step 1602 determines which phone
Determine whether SAC has been started. If the stimulus is from a covering phone, this is because the call to be covered by the covering phone came just after the CRI timeout and for some reason the covering subscriber did not want to answer it. It means something. In this case, the SAC stimulus causes the call to be transferred to the next covering station in the covering path, if one exists. To accomplish this, subroutine FND-CVPT is called in step 1604 to find the next covering telephone, if one exists. If not present or if the remaining covered phones are unavailable, the SAC
Request will be ignored. If a cover telephone is available (step 1605), then in step 1603, the capture of the vacant storage terminal in the cover telephone is released, and the display, if any, is turned off. If the next covering telephone is MC104 (step 1606), the step 1609 call state is set to CALLER-RESP-INTV-GRP to reflect that the call has been redirected to the MC group and to continue CRI. This will return you to the main program. If the next covered telephone is an individual telephone, step 1607 seizes the telephone's free call storage terminals, initializes the display module, if present, and returns to the main program to continue CRI. .

Full Call Transfer During Covering Ringing It may be the case that at covering telephone 902 (or at other covering telephones) a SAC stimulus is being received during the ringing of the calling transfer path. With this stimulus, the program shown in Figure 17
It will return to CV-SAC1. Step 170
In step 3, program trunk record item FAC2
Determine that the SAC stimulus is being applied from the cover phone by checking . If the stimulus is from the calling or primary telephone, the stimulus is ignored. If the stimulus is a covering telephone, the program proceeds to forward the call to the next covering telephone in the appropriate covering path with the remaining steps of FIG. 17 described above.

Transfer all calls during the D/A timing of the main telephone In the previous example of D/A cover, external calls are transferred to telephone 90.
It will be recalled that the D/A timing is set in step 1312 and the primary telephone ring is initiated. Here the SAC function is activated on the primary phone while ringing occurs during the D/A timing time.
Assume that the SAC function has been activated. Activation of the SAC causes SAC stimulation to be generated as described above. The starting state is PRINC-DA-ICOM-RING. Due to this stimulation, as shown in FIG. 12, CV-STA2 in FIG. 18 is entered. In step 1803, CV-STA2 verifies that the SAC activation came from the primary phone. Otherwise, it is ignored. If activation occurs at the primary telephone, then the program proceeds to transfer the call as described above.

Implicit Primary Phone Address To illustrate an example of an implicit primary phone address, let us now assume that a conventional call that was transferred to cover phone 902 was answered at that phone.
Let us also assume that the call to the main telephone is so important that it is worth interrupting the host in the conference. Therefore, the covered subscriber is phone 1
Suppose that the user wishes to inform the host at 001 to answer the call via a meeting call. The primary telephone has the ability to answer calls to a simulated bridge terminal (SBA) maintained at the primary telephone of the illustrated system for the originating call receiving terminal from which the call originated. SBA is not necessary for understanding the implicit primary phone address, so it will not be discussed further.

The cover subscriber of the telephone 902 presses the conference button 31
3 or by pressing transfer button 312 to place the covered call on hold. This also automatically selects the idle call storage terminal of the covered telephone and then presses the meeting button 311. As a result of the operation of the meeting button, the system executes the routine CV-
Enter CSLT1. The cover telephone index is given to CV-CSLT1 as an input parameter.
In step 2103, CV-CSLT1 obtains the ILN of the storage terminal while on hold to obtain the trunk record of the covered call. This is table EKT−STA2
This is done by using the phone desk to obtain the button number of the reserved selection button from the CXF-LN. This button number is then translated to the ILN of the reserved storage terminal. The CXF-LN is stored along with the button number by a conventional program (not shown) that manages button operation. To confirm that the call held on the calling telephone is a covered call, step 2104 includes
The item REDIR-TYPE in TRKTBL6C is tested. If it is not a cover call, the button action is ignored. CV-CSLT1 then steps 2106
, where the ILN of primary telephone 1001 is retrieved from TRKTBL6B of the trunk record of the covering call (Figure 5) and the primary telephone associated with the currently held call terminal of the covering telephone is automatically retrieved for the implied primary telephone address. be identified. The ILN is translated into a primary telephone number that is used to set up a call from cover telephone 902 to primary telephone 1001.
In step 2107, the item TOLL-BIT is set to indicate a priority call.
TRKTBL3 (Figure 5) is set. In step 2108, TRKTBL7 (Figure 5) items D1 to
The telephone number of the main telephone is stored in D4. Finally, in order to simulate the state in which dialing of the telephone number of the main telephone is completed, in step 2109,
At TRKTBL1 (FIG. 5), the call progress mark PM1 for the meeting call is set to a predetermined state. CV-CSLT1 then returns to the main program. The completed dialing mark now given to PM1 and the primary telephone number stored in the trunk code create a condition in which the call is dialed from the cover telephone, allowing the primary program to set up the necessary call connections. In response to a meeting call, the main program uses the steps shown in Figure 13 to determine whether call coverage is applicable to this call.
Enter CPRTN63. TOLL- in step 2107
Since BIT is set, step 3704 of subroutine CVR-CHK called by CPRTN 63 eliminates the possibility of forwarding the meeting call to the covering telephone. A call is made to the main phone with a special priority alert signal (not explained) to notify the host that a priority call has arrived regardless of its coverage and SAC status. After the host answers the conference call, the covering subscriber of telephone 902 can automatically connect to both the main telephone and the calling telephone by pressing the transfer key, and connect to the calling telephone by pressing the conference key. A three-way conference can also be held between the user and the main phone.

Leave Word Calls and Cover Call Back In the following examples describing LWC, this feature can be activated from any answering telephone, e.g. a covering telephone as mentioned earlier in this specification, as well as call pickup, call following, etc. I want you to understand that.

Here, the calling party of telephone 1001 is telephone 901.
Let's assume that you called 901 has conditions that cover all internal and external calls, so
The call is transferred to the covering telephone. The call is answered at cover telephone 902. Furthermore, rather than making a simple callback request, the calling party
I would like to leave a message for the owner of number 1. This message could be, for example, ``If delivery is not made within this week, the order contract may be cancelled.''
It might be something like that. This message is picked up by the covering subscriber at telephone 902. The covered subscriber now wishes to call the owner of telephone 901 to take a message. To do this, the covering subscriber presses the LWC button on telephone 902. This button operation is detected by the system and uses the activation phone index as an input parameter as shown in Figure 22.
I will be joining LWCABTN1. The program covers the phone index in step 2200 according to the selected power supply terminal of the phone.
Translate to ILN. In step 2201, the program determines whether an LWC message has already been stored for this program by examining the item LWC-ACT-ON. A second LWC message request for any call will not be accepted, in which case the program will return to the main program at 2202. LWC−ACT
-ON is not set, the program determines whether cover phone 902 has the right to initiate LWC messages. This is the table of LCOST4 (Figure 4) in step 2203.
This is done by examining the items LWC-SND-ASG. If the activated phone does not have the authority to operate LWC messages, the LWC lamp on the phone LWC button will flash in step 2204 and the request will be ignored. telephone 90
2 is authorized to operate LWC messages, the program determines in step 2205 whether a call record has been created for this call. A call is always present unless the calling party receives a busy tone. LWC call processing stimuli are generated in step 2206 and 22
At 07, the program returns to the main program. In response to the call status of PM1 in Trunk Table 1, the LWC stimulus enters program LWCABTN2 in Figure 23 if the LWC is activated during the caller response time (CRI) or ringing condition; If activated during busy state, LWCABTN3 (26th
(Figure). If the LWC function was activated before the main phone was dialed, the stimulus will cause LWCACT1 (Figure 27) to be entered.

In the present example, it is assumed that the calling telephone 1001 and the cover telephone 902 are in a conversation state when the LWC of the telephone 902 is activated. Therefore, step 2206
By the occurrence of the LWC stimulus in the 26th
You will enter the program LWCABTN3 shown in the figure.
The program displays the line status table in step 2601.
The extension trunk number (ITN) of this call is obtained from the item TRKNUM of LSTWD1 (Figure 6). Principal telephone 901 is identified for the implicit principal telephone address in step 2602 by obtaining the principal telephone ILN from trunk table 6B. If item LWC−
The RCV-ASG indicates that the main phone 901 is not allowed to receive LWC messages (step 2604), and the program starts with the LWC of phone 902 started in step 2605.
The lamp will blink and the program will return to the main program. If the main phone 901 is allowed to receive LWC messages, the trunk list is displayed in step 2606.
By examining the item REDIR-TYPE from 6C, the program determines whether this call is a forwarded call. The purpose of this step is to send the calling telephone 100 to the calling telephone 100 for the purpose of the LWC message being generated.
This is to determine which of the telephones 1 and 902 is to be handled as the calling telephone. In this example, since cover phone 902 has activated the LWC feature, the program in step 2607 generates an LWC message that identifies cover phone 902 as the calling phone and sends an SND-
Store the telephone number 902 in XCT-EXT. The ILN of both the initiating phone and the primary phone is translated into a phone number for message storage. In step 2608, the subroutine is used to send the LWC message to the DCIU interface program.
SND-STOR is called. SND-STOR is the second
This is shown in Figure 5. This routine stores the LWC message in the buffer area and sends it to the DCIU.
An interface (program not shown) unwords and transmits to AP 103. Step 25
00, SND-STOR first sets the message type item SND-XCT-TYPE of the message transmission block SND-XCTB (FIG. 7) to indicate storage of an LWC message. In step 2501, the subroutine
Move the contents of XCTB to the DCIU for transmission to the AP.
This subroutine then proceeds to step 26 in FIG.
Return to the calling program at 09. At step 2609, the LWC lamp of the starting telephone 902 is turned on, and when the generation and storage of the LWC message are completed, the program returns to the main program.

Let us assume for a moment that step 2606 did not forward the call to a covering telephone. This is the situation that arises, for example, when a subscriber other than the desired master answers at the main telephone. Suppose that the calling subscriber (or the answering subscriber) attempts to activate the LWC feature rather than the answering subscriber manually picking up a message for the primary telephone. In this case, it is first identified in step 2610 that both the calling telephone and the primary telephone are extension telephones. Otherwise, no LWC message will be generated. If both phones are extensions,
The program generates an LWC message in step 2611 and sends the calling telephone 1 to SND-XCT-EXT.
The number 001 is stored in SND-XCT-BUF, and the number of the main telephone 901 is stored in SND-XCT-BUF.

When activation of the LWC button is first received in FIG. 22, in step 2205 it is assumed that there is no call record (caller receives busy tone).
The program returns LWC-ACT-ON with 2211 to indicate that the LWC message is stored.
Set. The busy tone for telephone 902 is 2
It is removed at 212. The ILN of calling telephone 902 is translated into a calling telephone number in step 2213.
The number of the calling telephone 901 is displayed in step 2214.
Obtained from item LAST-NUM of EKT-STA2. These telephone numbers are stored in step 2219, and subroutine SND is executed in step 2215.
- Sent to the application processor by STOR. At this point, the program will run on the LWC-activated phone 9.
Generate a confirmation tone for 02, step 22
Turn on the LWC lamp at 16. Step 221
At 7, the program begins a timing period that times the confirmation tone. This generates a call record for this call and sets the call progress mark PM1 to state TIME-- in step 2218.
Set LWC-ACT-TONES and return to the main program. When the confirmation tone period times out, program LWCBTN2B of FIG. 24 is then entered.
A line-free stimulus in the above call state means that one of the lines in this connection has gone off-hook, which will also enter LWCBTN2B.
The program first determines in step 2400 which of these stimuli caused entry into the program. If a line empty stimulus is given, the program cancels the timing of the tone in step 2401. In either case, the tone is removed in step 2402 and all call registers associated with this call are removed in step 2403.
It is cleared with . At this point, the LWC function is completed and
This will return you to the main program.

Upon successful storage of the LWC message in each of the above examples, the following steps are performed to illuminate the Automatic Message Waiting (AMW) lamp associated with primary telephone 901 and all extensions of that AMW lamp in response to a message from AP 103. Then, the program AMWLPCTL shown in Figure 30 will be entered.
Upon entering AMWLPCTL, it is given the telephone number 901 whose AMW lamp is to be updated. This is translated into ILN in step 3000. In step 3001, the table
The program determines if there is an entry for this ILN in AMWPTRS. If present, the item LAMPTR is read from this table to obtain the appropriate address pointers for tables AMW-APP1 and AMW-APP2. Step 3002
Now, from each of these tables, the first entry and the next entry are obtained. If AMW−APP1
If it is determined by step 3003 that telephone 901 is not a multi-function telephone according to item AMW-STA-NUM from table AMW-APP2, the program then retrieves item AMW-BTN-ID from table AMW-APP2.
Translate the ILN and use this information to create the appropriate AMW
Turn on the lamp. This operation is performed in step 3004.
and 3005 occur. On the other hand, if AMW
- Light the appropriate lamp using the identification number obtained from the item AMW-BTN-ID in APP2. This occurs at step 3006. step 300
At 7, the program examines the flag LAST-APP from table AMW-APP2 to determine if this is the content of the last message waiting lamp to be updated. If there are other lamp entries, it repeats the steps described above, and if there are none, exits to the main program.

by the caller at telephone 1001 during the Caller Answer Interval (CRI) or during the ringing of covering telephone 902 (or any telephone).
Let's assume that LWC has been started. The LWC stimulus generated in step 2206 will then enter program LWCABTN2 of FIG. In this case, if you have the qualifications,
An LWC message is generated and the call is terminated. By translating the calling telephone's index as before, LWCABTN2 obtains the ILN of principal telephone 901 in step 2300. Step 2301
This cancels the forwarded feedback tone (RFT) and CRI or primary phone D/A timing, if any. Step 2302 then turns off the ringing and ringback signals for the appropriate telephones. This removes the called telephone connection in step 2303 and then connects the called telephone in step 2304.
From LWC-RCV-ASG, main telephone 901
Determine whether you are eligible to receive LWC messages. If not, the program flashes the LWC lamp and sends an abort tone in steps 2305 and 2306 to inform the initiating phone 1001 that the message generation has failed. In step 2307, settings are made to time an interruption tone of, for example, 10 seconds. However, assuming that telephone 901 is qualified for LWC messages, in step 2310 the program stores the numbers of calling telephone 1001 and primary telephone 901 in message sending block SND-XCTB. The message is sent to the DCIU interface program at step 2311. Step 23
At 12, the LWC lamp of the telephone 1001 is turned on. At step 2313, a confirmation tone is sent to telephone 1001, and at step 2314, the timing of the confirmation tone is set. Finally, step 2315
The call processing state is TIME−LWC−ACT−TONES
, and will return to the main program while calling telephone 1001 is given a tone.
As mentioned above, when the tone time expires,
It will enter LWCBTN2B (Figure 24).

By taking the telephone off-hook and activating the LWC function before dialing the digits of the principal telephone for which the message is to be stored, LWC message storage can be effected without ringing the principal telephone. The program LWCACT1 of FIG. 27 will be executed to collect the main phone digits as they are dialed as a result of LWC activation before the main phone digits are dialed. Also, upon activation of LWC by dial access code (DAC) or reception of LWC cancel DAC, LWCACT1 is executed to collect the digits of the main telephone. The trunk number and ILN of the initiating telephone associated with the call are obtained at step 2700. If the stimulus entered into this program was caused by the LWC button, steps 2701 and 2702 illuminate the activating phone LWC lamp. If the initiating phone has permission to send LWC messages (step 270)
5) The primary telephone number is obtained from the initiating telephone in real time as shown by the dotted block in step 2706. Thereafter, the program for performing the function of generating or canceling an LWC message enters LWCACT4 in FIG.

The stimulus that enters LWCACT1 is a press of the LWC button (step 2707) and the activating phone is LWC
If the user is not authorized to send the message (step 2705), the LWC request is denied. However, the dial tone may still be present on the boot phone. When the calling party begins dialing the digits on the primary telephone, the dial tone is removed by the primary program as usual. The program therefore removes the dial tone from the activation telephone at 2708, flashes the telephone's LWC lamp to indicate the rejection, and returns to the main program where an interrupt tone is provided.

After the primary telephone digits are collected in step 2706, LWCACT4 (Figure 29) is entered. The number is translated into ILN at step 2900. In step 2901, the primary phone uses LWC messages to determine whether it is authorized to receive LWC messages.
-RCV-ASG can be investigated. If there is no authority, the request will be denied. In step 2902, if the phone is a feature phone, the LWC
The lamp will flash and an interrupt tone will be given to the main program. If not,
A determination is made whether the stimulus that caused LWCACT4 to be entered is a DAC of LWC cancellation.
If not, the stimulus is either a button or
The LWC request will be made by the DAC. In this case, in step 2904 the program launches ILN
into that phone number, generate the requested LWC message in step 2905, and
At 906, it is sent to the DCIU interface program. Step 2907 turns on the activation LWC lamp if applicable, sends a confirmation tone to the activation telephone 2908, and returns to the main program upon completion of the requested function.

If the above stimulus is a cancellation DAC, then
by the primary telephone number and the initiating telephone number received in step 2706 as part of the request.
It is determined which message stored in AP 103 is to be canceled. The cancellation request executes step 2910, where item MSG-
LCK-ASG is examined to determine if the initiating phone is ready to lock. A locked phone can also retrieve LWC messages.
You can also cancel it. Therefore, if the phone can be locked, the item MSG-
UNLCKD determines whether the phone is actually locked. If so, step 2
Through 902, the program ends. If the telephone is not locked or is determined to be unlockable at step 2910, a cancellation message is generated at step 2912. This message is sent by the subroutine SND-CNCL shown in Figure 25.
Sent to DCIU interface program.
SND-CNCL is shown in FIG. In step 2502, the subroutine selects a message type item indicating a cancellation message.
Set SND-XCT-TYPE. It then transfers the message to the DCIU and returns to the program that started it, where step 2908 sends a confirmation tone, thereby completing the cancellation request.

A Covered Callback (CC) message initiated by a Covering Telephone, except that it requests the master to call the calling subscriber rather than the Covering Subscriber, originates at the Covering Telephone. Similar to the LWC message sent. For example, consider that the call described above from telephone 1001 to telephone 901 was covered by telephone 902. The covering subscriber at 902 presses the LWC button instead of the LWC button to inform the master of telephone 901 to call the subscriber at 1001.
I might press the CC button. When the CC button is pressed, this is detected by the system and the second
This will enter the program CVCBRTN shown in Figure 8.
This program is given the activation telephone index as an input parameter. CVCBRTN first sets the index of the starting phone in step 2801.
Translate to ILN. In step 2802, this is
Using ILN, if a trunk record exists for the call, the trunk table index (ITN) is retrieved from item TRKNUM in line state table LSTWD1.
get. If a trunk record does not exist, button operations are ignored. Using the ITN, the program obtains trunk records in step 2803. In steps 2804 and 2805,
The program determines from the fields REDIR-TYPE and TL1 whether the call is forwarded and whether the calling telephone is an extension telephone. If the call was not transferred to a covered subscriber,
The operation of the cover call back button is meaningless. Additionally, cover call back messages are not generated for calls from outside lines. Therefore, if any of these checks are negative, CVCBRTN ignores the CC stimulus and returns to the main program. In steps 2806 and 2807, the program determines if a CC message has already been generated for this call and if the calling telephone
Determine whether you have the authority to send LWC-type messages. If a CC message has already been generated or the calling telephone is not eligible, step 2811 indicates to the initiating telephone that the request has been denied by flashing the initiating telephone's CC lamp.

In step 2809, as part of the implicit principal telephone address operation, the program identifies the principal telephone by reading PRINCIPAL in the trunk record. The primary phone is eligible to receive LWC messages in step 2810.
If the primary phone is not eligible, the CC request is denied.

If all of the above tests are successful, the program proceeds to generate and store a CC message. At step 2808, CVCB-ACT-ON
is set. In step 2812, it translates the primary phone's ILN into the appropriate phone number. In step 2813, enter the main phone number as SND-XCT-
A CC message is generated by storing the calling telephone number in the BUF in SND-XCT-EXT.
This is then followed by the subroutine in step 2814.
Call SND-STOR and send CC message to DCIU interface program. The program lights up the CC lamp of the startup phone in step 2815,
When completion is displayed, the program returns to the main program.

As a result of lock/unlock DAC stimulation,
Execution of the program LWC-LCK of FIG. 31 which is executed places the telephone in lock mode. boot
ILN is given to the program as an input parameter. Only feature phones can be put into lock mode. This is determined in step 3101. If the phone is a feature phone, step 310
At step 2, the ILN is translated into a telephone number, and a determination is made at step 3101 whether the telephone has a display set. Step 3104
The request is denied if it is found from the items MSG-LCK-ASG that the initiating phone does not have permission to enter lock mode. Otherwise, step 3
At 105, the DAC stimulation is examined to determine whether a lock request or an unlock request was made. Accordingly, step 3106 or 3
At 107, MSG-UNLCKD is set or
be cleared to put the phone in the correct mode,
A confirmation tone is sent to the initiating telephone at step 3108, completing execution of the program.

Message search If a message from LWC, CC or Message Center is displayed on the phone, the application processor 10
3, the automatic message waiting (AMW) lamp on that phone will automatically light up. The owner of the phone with the display module
LWC and CC messages can be viewed on the display module. In this example, the display is a 40-character character display, so a message center message of no more than 40 characters can also be obtained with the display set. If the host does not have a display, he can call someone to handle it, such as a secretary or MC operator, to retrieve the message.

To initiate a message search, the subscriber presses the message search button 306 on the display module. A person handling the message, such as a secretary, uses the cover message search button 307. This generates a stimulus, which in turn causes the program in Figure 32 to
You will be entering PMRBEGIN. Step 320
If it is determined at 1 that the phone is locked, the request is denied. Otherwise,
PMRBEGIN gives the DCIU interface program a message requesting the first two messages stored for this primary telephone. When the buffer is selected by an instruction under control of the program, the contents of the buffer are displayed on the display module. Step 3
At 202, PMRBEGIN enters a message "Search in progress" in buffer 1, and a message "message to (telephone number) (master name)" in display buffer 2. The display phone number is the number given to PMRBEGIN when entering the program. The displayed host name is read from the host name database. The master name database stores subscribers associated with telephones.
In this example, the master name database is stored in the control processor's memory 108. Step 3
At 203, PMRBEGIN sends a command to the phone to select buffer 1 for display. It then returns to the main program and waits to receive the requested message from the DCIU interface program.

When the first message arrives from the application processor 103 via the data channel 111 and the DCIU 110, the RTMG-RCV shown in FIG. 33 is called by the DCIU interface program. The program causes a message to wait in a message queue (not shown) at 3301 and ends. Each incoming message similarly enters the RTMG-RCV where the message queues. Figure 34 Program DSP
- TSK is called periodically by the main program to manage messages. The program determines in step 3401 whether the queue is empty. If not, this puts the message at the head of the queue for this phone into the next display buffer (which is the third display buffer for the first message sent from AP 103). . If this is the first message to be returned (step 3)
403), the DSP-TSK module sends a command to display the second buffer to the display module in step 3404. This includes the host and the host's phone number as mentioned above. If the message stored in the next buffer is not the first message in response to the display request,
DSP-TSK returns to the main program without performing any further operations. From then on, the display is performed in response to the operation of the step button 309 on the display module. Assuming that such a step button operation is performed by the master, the program MR-STEP shown in FIG. 35 is executed. At 3501, a request is made to the DCIU interface program to retrieve the next message stored in application processor 103 for this telephone. MR−
The message in the next display buffer of the main telephone is then displayed in step 3502 according to the command from STEP. This completes the execution of MR-STEP by one step button operation. Execution of MR-STEP is repeated in response to each step button operation until the display mode is terminated.

The displayed message is held in the application processor 103 until it is deleted by operating the display set delete button 308. By operating the delete button, the program MR in Figure 36
-DELETE is executed. In steps 3601 and 3602, the program displays a delete indication on the display by storing in the current display buffer and sending a delete message to the DCIU interface program. Details regarding which messages to delete in the application processor 103 are contained in the messages of the DCIU interface program.

It should be understood that the configurations described above are merely illustrative of the application of the principles of the present invention. It will be apparent to those skilled in the art that other arrangements may be devised without departing from the spirit and scope of the invention.