JPH0362345B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a switching system capable of accommodating a mixture of two-wire telephone terminals and four-wire telephone terminals.

Generally, a button telephone (key telephone)
In addition, switching systems that accommodate multifunction telephones that have many function buttons and can perform various services other than telephone calls are currently under development. It also includes a two-wire control line for transmitting and receiving lamp control signals, etc. When accommodating a 4-wire telephone terminal connected to the speech line and control line,
In addition to controlling the exchange connection of normal telephone lines, the main control unit also controls the ringer and connection of each telephone terminal using the above control line.
It is also necessary to control lamps, etc.

Therefore, in exchanges that accommodate only 2-wire terminals or only 4-wire terminals, the control can be handled by providing a dedicated control device that accommodates each terminal, but furthermore, it is possible to control this by providing a dedicated control device that accommodates each terminal. A switching system that accommodates a mixture of telephone terminals and four-wire multifunctional telephone terminals will be required by future communication formats, such as building-installed telephone systems.

[Prior Art] Conventionally, switching systems that accommodate both 2-wire telephone terminals and 4-wire telephone terminals require complicated control of the switching equipment, making it difficult to achieve versatility. Techniques such as installing a separate switchboard for accommodating two-wire telephone terminals and making the entire system into a switching system have been taken.

FIG. 18 is a block circuit diagram showing an example of a conventional switching system accommodating a four-wire telephone terminal. In the figure, call information from a 4-wire telephone terminal A or B is transmitted through a 2-wire (2W) call line l ₁
and subscriber control circuit (LNC) 184 or 1
Immediately after passing through the voltage conversion circuit 85, the voltage is drawn into an exchange switch (SW) 181, and then sent to a private branch exchange or other office via an internal telephone trunk (IOT) 187 or a central branch trunk (BWT) 186. , a well-known communication path is formed.

Control information such as call information, key information, etc. from the 4-wire telephone terminal A or B is transmitted through the control line l ₂ consisting of 2 wires (2W) and the subscriber control circuit 184 or 18.
5 and the bus line BUS directly by the main controller (MC) 182, and the control signals for controlling the blinking of the lamp, ringing of the ringer, etc. in the 4-wire telephone terminal A or B are as follows: Main control device 1
82 to the four-wire telephone terminal A or B via subscriber control circuits 184, 185 and control line _l2 . Note that 183 is a storage device MEM that stores programs, data, etc. necessary for exchange control.

Furthermore, in order to mix 2-wire telephone terminals and 4-wire telephone terminals within the same facility, the conventional method used is to install a switchboard that accommodates only 4-wire telephone terminals (for example, A), as shown in Figure 19. (Also called exchange device, main device, etc.) (EX ₁ ) 191
The entire system is constructed by connecting an exchange (EX ₂ ) (for example, a private branch exchange) 192 accommodating a general two-wire telephone terminal (for example, C) to an upper level.

Four-wire telephone terminal A is connected to exchange switch 193 via subscriber circuit 196 as in FIG. 18, and control information is exchanged with main controller 194 and storage device 195 via a bus.
On the other hand, the two-wire telephone terminal C is a subscriber circuit (LC).
202 to the conversion switch 198;
The exchange is controlled under the control of the main controller 199 and the storage device 200. Each exchange 191, 192 connects other exchanges with bidirectional trunks 197, 201, 20.
2, 203 (or output trunk, input trunk, etc.). Therefore, as a switching system, switchboards 192 and 191 were installed in the same premises etc., connected by trunks 197 and 201, etc., and 2-wire/4-wire
It is customary to have a system that accommodates a mixture of wired telephone terminals.

As described above, in the past, two types of switching equipment for two-wire and four-wire systems had to be installed separately within the same facility, which posed a problem in that the scale of the hardware was large and the value was high.

In Figure 19, the exchanger for 4-wire system (EX ₁ )
It is also possible to accommodate a two-wire telephone terminal in the switch 191, but in order to do so, the main controller 194 in the exchange 191 has information that identifies a four-wire telephone terminal and a two-wire telephone terminal, must be identified at all times, resulting in an extremely heavy load on the software of the main controller 194 and a problem in that the processing becomes complicated.

[Problem that the invention seeks to solve]

SUMMARY OF THE INVENTION In view of the above-mentioned problems in the prior art, an object of the present invention is to accommodate a mixture of 2-wire telephone terminals and 4-wire telephone terminals within one switching system, which increases the burden on the software of the main controller. Our goal is to provide an exchange system that makes it possible without any problems.

[Means to solve the problem]

The present invention provides a subscriber circuit that interfaces between the exchange main body side and the telephone terminal side, a subscriber circuit that connects to a 2-wire telephone, and a subscriber circuit that connects to a 4-wire telephone, and each subscriber circuit and the main controller of the exchange interface with the same means that interfaces with the 4-wire telephone terminal, thereby converting the exchange of control information for the 2-wire telephone terminal into the same control information as that of the 4-wire telephone terminal. The subscriber circuit for the two-wire system is provided with a means for doing so.

FIG. 1 is a block diagram showing a schematic configuration of an exchange system according to the present invention. In the figure, 1
is the exchange switch SW, 2 is the main control device MC, 3
is a storage device (memory) MEM, 4 is a two-wire subscriber interface circuit SUB1, 5 is a four-wire subscriber interface circuit SUB2, and 6 is a trunk (for example, a bidirectional trunk) BWT that interfaces with other exchanges. 7 is a trunk IOT that performs interconnection within the own exchange, 8 is a two-wire telephone terminal TEL1,
9 is a 4-wire telephone terminal (TEL2).

The exchange system according to the present invention includes an exchange switch, a main controller 2 that controls the exchange switch 1,
Switch 1 to exchange the call line from the 4-wire telephone terminal 5
A four-wire subscriber interface circuit 5 connects a control line for connecting to the main controller 2 and exchanging control information to the main controller 2, and a communication line from a two-wire telephone terminal 8 is connected to the exchange switch 1. The control line for exchanging control information with the main controller 2
A two-wire subscriber interface circuit 4 is provided for connection to the subscriber interface circuit 4. The two-wire subscriber interface circuit 5 includes a means for converting changes in the potential of a communication line connected to the two-wire telephone terminal 8 into digital information and transmitting the digital information to the main controller 2, and a means for transmitting digital information from the main controller 2. means for performing ringer control of the two-wire telephone terminal 8 based on The same applies to terminals.

Here, the two-wire subscriber interface circuit 4, the four-wire subscriber interface circuit 5, and the main controller 2 are connected through the same interface, and when looking at the telephone terminal side from the main controller 2, It is now possible to control the terminal without being aware of the distinction between 2-wire and 4-wire terminals. That is, in the present invention, the interface between the exchange switch SW and the telephone terminal is a 2-wire type and a 4-wire type interface instead of the conventional subscriber control circuit LNC.
It is noteworthy that it is a wire-type subscriber interface circuit.

[Effect]

By processing the 2-wire subscriber interface and 4-wire subscriber interface in each subscriber interface circuit, and using the same interface on the exchange side, both can be controlled by the main controller. Therefore, two-wire telephone terminals and four-wire telephone terminals can be mixedly accommodated in one switching system.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 2 is a block circuit diagram illustrating a two-wire subscriber interface circuit (also referred to as a two-wire subscriber interface circuit) in accordance with one embodiment of the present invention.

In FIG. 2, the same reference numerals as in FIG. 1 indicate the same objects, and parts related to the present invention are shown in detail. Generally, a two-wire telephone terminal (also referred to as a two-wire telephone terminal) 8 includes a handset T ₁ , a communication circuit (NW ₁ ) 81 , a hook switch HS ₁ , a tone ringer TR that rings a bell etc. in response to a calling signal, etc. It is equipped with the following. A two-wire subscriber interface circuit (also called a sub-controller) 4 connected to the two-wire telephone terminal 8 connects communication lines (or subscriber lines) L ₁ and L ₂ to a DC superimposition transformer (T). A control unit (CONT1) 44 is connected to the exchange switch 1 via the telephone terminal 41, and controls the reception of on-hook, off-hook information, selection signals, etc. of the two-wire telephone terminal 8, and controls the transmission of a calling signal to the telephone terminal 8. , buffer memory (BMR,
BMS) 42, 43, a ring signal generation circuit (CRG) 49 for sending a ring signal to the telephone terminal, a switching relay circuit R and RS for sending a ring signal, a state detection circuit RT for detecting the state of the telephone, etc. We are prepared. Further, the control unit 44 further includes the main control device 2
Analyzer (CA) 45 receives control signals (control commands) from the telephone and analyzes the commands, Ringer transmission control section (RTC) 46 controls the transmission of ringing signals based on control commands, etc. Monitors and detects the status of the telephone status monitoring unit (LS) 48, main controller 2
It consists of a code converter (CV) 47, etc., which encodes and sends the necessary information to the computer.

On the other hand, the memory area of the storage device 3 is provided with an area MR for storing control commands sent from the main controller 2 to the sub-controller 4, and an area MW for storing control codes sent from the sub-controller 4 to the main controller 2. It is being The buffer memory 42 of the sub-controller 4 has a memory area.
The contents written in MR are read out and written, and are also stored in the buffer memory 4 of the sub-controller 4.
The contents written in 3 are written to the memory area MW.

Each memory area contains, for example, read control information (for example, other telephone terminals) consisting of 1 word and 4 bits.
information from TEL0 (not shown)) and write control information (for example, information from telephone terminal TEL1) are stored in a predetermined memory area.

Further, as the buffer memories 42 and 43, for example, RAM having a capacity of 327 words is used.
It is controlled by one sub-controller and has an appropriate capacity depending on the number of telephone terminals, number of buttons, etc.

FIG. 3 is a block circuit diagram illustrating a four-wire subscriber interface circuit (also referred to as a four-wire subscriber interface circuit) in accordance with one embodiment of the present invention. In FIG. 3, the 4-wire telephone terminal (TEL2) 9 includes a handset _T2 , a communication circuit ( _NW2 ) 96, a tone ringer TR switched via the communication circuit 96, and a switch _HS2 .
A key input section (KEY) 92, a lamp control section (LED) 93, a switch input section (HS) 94 linked to a switch, and a telephone call circuit.
The control unit (CNT ₂ ) 91 controls the NW ₂ , lamp control unit LED, tone ringer TR, etc., and generates a control code based on input information from a key input unit 92 and a switch input unit 94.
The control unit 91 performs the above control based on signals from the 4-wire subscriber interface circuit (also referred to as 4-wire sub-controller) 5, the key input unit 92, and the like. For this purpose, the control unit 91 uses the control line L ₃
and is connected to the sub-controller 5 via _L4 .

The sub-controller 5 has an interface between the four-wire telephone terminal 9 and the exchange side, and connects the telephone line
In addition to the L ₁ and L ₂ interfaces, the previous control line L ₃ ,
It is provided with a control unit (CONT2) 54 for receiving/transmitting input/output information from _L4 , and buffer memories (BMR, BMS) 52, 53 for exchanging information with the main controller 2. The control unit 54 includes a command analysis unit (CA') 55 for analyzing control commands from the main controller 2 and sending control codes to the 4-wire telephone terminal 9, and a command analysis unit (CA') 55 for analyzing control commands from the main control device 2 and sending control codes to the 4-wire telephone terminal 9; code converter (CV') 5 that sends the control code from the code to the main controller 2
It consists of a transmitting section (S) 59, a receiving section (R) 58, etc., which are in charge of transmitting and receiving control codes to and from the control section 91 of the 6 and 4-wire telephone terminal 9. Also, buffer memory 5
The communication with the main controller 2 and the storage device 8 via the terminals 2 and 53 is the same as in the case of the two-wire telephone terminal described above.

That is, the main feature of the present invention is shown in FIGS.
The purpose is to be able to perform processing with exactly the same control regardless of the four lines.

In this way, the subcontroller 5 controls the reading side memory area MR and the writing side memory area MR.
MW, and buffer memories 52 and 53,
Commands are exchanged with the main controller 2.

FIG. 4 is a flowchart showing the calling operation of the two-wire telephone terminal TEL1 in the circuit shown in FIG.
In the figure, when the handset _T1 of the telephone terminal TEL1 is lifted at (1), the hook switch _HS1 is closed and a loop is formed in the communication lines _L1 and _L2 . The loop status monitoring unit 48 in the subcontroller (SUB1) 4 scans the subscriber's loop status at intervals of, for example, 5 msec, and detects the off-hook of the telephone terminal TEL1 (2). When the status monitoring unit 48 detects an off-hook, it writes the control code "off-hook" information into the area MW of the writing side memory (MEM) 3 via the buffer memory 43 (3.) Main controller (MC) 2 reads the "off-hook" information written in the memory (MEM) 3 (4) and performs the necessary exchange connection processing corresponding to the off-hook (5.) Then, the extension switch trunk (IOT) 7 is connected to the exchange switch. By connecting via the SW, a dial tone DT is sent to the telephone terminal TEL16.

The subscriber who picks up the handset T ₁ sends out a dial (7). The status monitoring unit 48 in the sub-controller (SUB1) 4 detects the "dial" information by loop scanning (8) and stores it in memory. (MEM) 3 in a predetermined area MW (9.) The main controller 2 reads the "dial" information written in the memory MEM3 (10), and selects the destination corresponding to the "dial" information. Necessary exchange connection processing such as calling is performed (11). Then, the called party's telephone is called, and when there is a response from the called party, a telephone call is made (12).

Next, when you hang up the handset _T1 , the
HS ₂ is opened and the loop of communication lines L ₁ and L ₂ is released (13). The status monitoring unit 48 in the sub-controller (SUB1) 4 uses a loop scan to
Detects the on-hook of _T1 (14) and writes this to the memory (MEM) 3. (15). The main controller (MC) 2 reads 16 the "on-hook" information written in the memory (MEM) 3 and performs the necessary exchange connection processing corresponding to the on-hook (17).
The line is thus disconnected.

FIG. 5 is a flowchart showing the incoming call operation of the two-wire telephone terminal TEL1 in the circuit shown in FIG.
In the figure, when there is an incoming call to the telephone terminal TEL1, the main control device (MC) 2 stores the calling side memory (MEM) in order to call the corresponding telephone terminal TEL1.
Write the ringtone sending command to area MR of 3 (2
1), (22). The command analysis unit CA in the sub-controller (SUB1) 4 receives the ringtone sending command from the memory (MEM) 3 via the buffer memory 42, analyzes it and sends it to the ringer sending control unit.
A ringer sending command is given to the RTC (23).
In response to this, the ringer transmission control unit RTC sends a 16Hz ringing signal to the tone ringer in the telephone terminal TEL1.
Send to TR (24). This causes the ringer of the telephone terminal TEL1 to ring.

Next, pick up the handset T ₁ and answer the incoming call.
The hook switch HS ₁ closes to form a loop (25), and the subcontroller (SUB1) 4 detects the off-hook state by scanning the circuit of the telephone terminal TEL1, stops the ring tone, and writes the memory (MEM) 3 on the writing side. "Off-hook" information is written in the area MW of (26), (27). The main controller (MC) 2 reads the area MW of the write side memory (MEM) 3 (28) to write to the telephone terminal.
When the response to TEL1 is confirmed, a command for instructing to stop the ringtone is written to the MR of the reading side memory (MEM) 3 (29), (30). Sub controller (SUB1)
4 receives the MR "stop incoming call" command from the reading side memory (MEM) 3 (31), but does not perform any particular processing because the ring tone has already been stopped (32). In this way, a telephone conversation is started (33).

Thereafter, the disconnection process is the same as that shown in FIG.
3 to the area MW of the memory (MEM) 3 (35), (36). The main control device (MC) 2 is
The on-hook state of the telephone is read from the area MW of the memory (MEM) 3 (37), and the communication path is released (38).

On the other hand, the 4-wire telephone terminal (TEL2) in the 4-wire subscriber line interface circuit shown in Figure 3
Flowcharts of the outgoing and incoming call operations by 9 are shown in FIGS. 6 and 7, respectively.

First, call control by the four-wire telephone terminal will be explained below with reference to FIG.

Lift up the handset at telephone (TEL2) 9 (41). At this time, a loop is formed via the lines L ₁ and L ₂ as in the case of the 2-line subscriber whose switch is closed, but the off-hook information is transmitted to the switch input section 9 linked to the telephone's switch.
4, the control unit 91 detects the off-hook and connects the control line.
The off-hook information is encoded and sent to the sub-controller (SUB2) 5 via _L3 and _L4 (42). The sub-controller 5 receives the code, rearranges the code as necessary in the converter 56,
Memory (MEM) 3 via buffer memory 53
(43). The main controller (MC) 2 reads the "off-hook information" written in the memory (MEM) 3 (44) and performs the necessary exchange connection processing corresponding to the off-hook (44).
5). Then, in the same way as described for the two-wire telephone (FIG. 4), the dial tone DT is transmitted through the telephone line by connecting to the trunk (IOT) 7 (46).

Next, all dial input from the terminal is performed through the key input section 92 (47), and each time the destination information (dial information) is detected by the control section 91, it is encoded and sent to the subcontroller (47).
8). When the subcontroller (SUB2) 5 receives the code information from the terminal side via the control line _L4 , it converts the code as necessary and stores it in the area of the memory (MEM) 3 via the buffer memory 53.
Write to MW (49).

The main controller (MC) 2 reads the “dial information” written in the memory (MEM) 3 (50)
As a result, necessary exchange connection processing such as calling the other party corresponding to the "dial information" is performed (51). Then, when the other party responds, the call state is established (52).

Disconnection occurs when the handset is put down (5
3) From the switch input section 94 to the control section 91
detects the on-hook and sends the on-hook information to the sub-controller (SUB2) 5 (54). The sub-controller (SUB2) 5 uses the buffer memory 5 in the same way as the off-hook, dial, etc.
3, the on-hook information is written to the area MW of the memory (MEM) 3 (55), and the main controller (MC) 2 reads the on-hook information from the memory (MEM) 3 (56) and performs the release process. Do it (57).

Next, the incoming call processing in the four-wire telephone terminal will be explained with reference to FIG.

When the main control device (MC) 2 receives an incoming call on the telephone terminal TEL1, it writes a ringtone sending command in the area MR of the reading side memory (MEM) 3 in order to call the corresponding telephone terminal TEL1 (61), (62). ).

The sub-controller (SUB2) 5 sends a ringtone sending command from the area MR of the memory (MEM) 3 to the command analysis unit 55 via the buffer memory 52.
(63), analyzes this command (64), and sends it to the telephone terminal (TEL) via the transmitter 57.
A ring tone command is sent to the control unit 91 of 2 (6
5). Upon receiving the incoming call command, the control section 91 of the telephone terminal (TEL) 2 performs controls such as making the tone ringer 95 ring and lighting a predetermined lamp of the lamp section 93 (66).

On the other hand, when the handset of the telephone terminal is off-hook (67), the control unit 91 detects the off-hook and sends off-hook information to the sub-controller (SUB2) 5 (68). The subcontroller (SUB2) 5 edits the command and writes the information into the area MW of the memory (MEM) 3 in the same manner as when sending (69).

When the main controller (MC) 2 confirms the response (70) from the memory (MEM) 3 (71), it notifies the sub-controller (SUB2) 5 of a ringtone stop command via the memory (MEM) 3 (72). ,(7
3). The subcontroller reads the ring tone stop command from the memory (MEM) 3 (74) and notifies it to the control unit 91 of the telephone terminal (TEL2) (7
5). The control unit 91 of the telephone terminal stops the ringtone (76). Then, it becomes a call state.

The disconnection is done by turning on the handset (78) as in FIG.
to receive on-hook information and off-hook information (7
9), on-hook information from the sub-controller (SUB2) 5 is notified to the main controller (MC) 2 via the memory (MEM) 3 (80), (81).

The main controller (MC) 2 receives the off-hook information and performs processes such as releasing the communication path.

As is clear from the above explanation of the operation, the control exchange between the subcontrollers (SUB1, SUB2) 4 and 5 and the main control device (MC) 2 according to the present invention is exactly the same for the 2-wire system and the 4-wire system, and It can be seen that in the controllers 4 and 5, the control is different depending on the 2-wire type and the 4-wire type, respectively.

Therefore, the present invention eliminates the conventional method of identifying each terminal and changing control in the main control unit when attempting to accommodate a mixture of 4-wire and 2-wire terminals on the exchange side. This not only makes it possible to unify control in the main controller, but also prevents program control from becoming complicated.

FIG. 8 is a diagram showing an example of control information given to the main controller from the 2-wire and 4-wire subcontrollers. As shown in the figure, control information
One word is composed of 8 bits 0 to 7 of DATAa, b, and c, and the state where the most significant bit "7" of a is "0" indicates an on-hook state. b
indicates a functional code, and c indicates each individual information. Therefore, the most significant bit “7” is “1”
Off-hook is detected. When the lower 6 to 0 bits are all "0" in the off-hook state, it indicates that no button has been pressed, indicating that there is no change in the terminal, and when the 6 to 4 bits are 001, the lower 3 to 0 bits are all "0".
Dial numbers 0 to 9, #, and * are indicated according to the bits, and when the 6th to 4th bits are 010, functions such as hold, group, central line call, etc. are indicated according to the lower 3 to 0 bits. When the 0 bit is 1010101, it represents a response to the test command. Furthermore, 2
The shaded portion of the wire interface indicates that no information is input from the two-wire terminal.

FIG. 9 is a chart showing an example of control information given from the main controller MC to the two-wire and four-wire sub-controllers. In the figure, when the most significant bit of d of the control information DATA is "0", it indicates a receivable state, and when it is "1", it indicates a receivable state. This information is used to notify the sub-controller of the processing status on the main controller side according to the traffic volume, and if it is unreceivable "1", one-way notification control will be performed from the main controller. It shows. When bit 6 of e and f of the control information DATA is "0", it indicates a visible display, and when "1" it indicates an audible display (functioning as a tone sound, etc.). Visual indication function (i.e. indicating lamp control function) is 4
Only the wire telephone terminal TEL2 has it, and the two-wire telephone terminal TEL1 does not have it. Control information 5
~0 bit indicates hold, group, station line call,...
..., represents various functions such as extension ringing, forwarded call paging, central office ringing, etc. control information
11000000 indicates tone off, 11111101 indicates reset, 11111110 indicates test command, and all "1" indicates NOP.

As can be seen in Figures 8 and 9, the main controller (MC) creates predetermined data for each control and sends it to the sub-controller, so if the sub-controller is a two-wire system and does not require control, the It will be automatically dropped in the controller.

Also, when sending a control code from the sub-controller to the main control device, in the case of a two-wire system, one without a control code is not automatically created, so there is no problem with exchange control. .

FIG. 10 is a circuit diagram showing in detail the calling signal sending circuit in the two-wire subscriber line interface circuit (subcontroller 8) shown in FIG. In FIG. 10, the calling signal sending circuit to the tone ringer TR is realized by including a CR signal generating circuit CRG and relay circuits R and RS.
When the main controller 2 receives a calling signal for the telephone terminal TEL1 from an extension or office line telephone terminal (not shown), the control unit 44 of the sub-controller (SUB1) 8 drives the relay circuit R corresponding to the telephone terminal. Then open the contact γ and connect the communication lines L ₁ and L ₂ .
It is connected to the CR signal generation circuit CRG, and provides a ringing-on signal RG to the CR signal generation circuit CRG.
When the CR signal generating circuit CRG receives the ringing-on signal RG, the CR signal generating circuit CRG generates the communication line L ₁ ,
Sends a 16Hz continuous ringer signal CR to _L2 . The telephone TEL1 receives this continuous ringer signal CR and generates a ringing ring tone. When the handset T ₁ is lifted, a loop is formed in the communication lines L ₁ , L ₂ ,
The current flowing through the communication line _L2 is detected by the photocoupler PC in the state detection circuit RT, and a detection signal is given to the control section 44. That is, this state detection circuit also serves as a ring top function. The control unit 44 scans the loop status of the subscriber at intervals of, for example, 5 msec, and determines that the handset _T1 has been taken off-hook when it detects through the scanning that the photocoupler PC remains on for at least 80 msec or more. In this way, the off-hook and dial pulses of the telephone terminal TEL1 are detected by the state detection circuit RT, and the sub-controller SUB1 receives the detection signals.

Note that the relay circuit R has a plurality of (e.g. eight) relay circuits.
A plurality of CR signal generation circuits are provided corresponding to telephone terminals, and the output of the CR signal generation circuit CRG is connected to multiple pairs of relay contacts, so that the ringer signal CR is sent only to the called telephone terminal. ing. The ring-on signal RG is a 16Hz signal that is output when at least one of the plurality of telephone terminals mentioned above is called.
This is the signal.

Figure 11 shows the CR signal generation circuit shown in Figure 10.
FIG. 2 is a detailed circuit diagram of CRG. In Figure 11,
The CR signal generation circuit CRG is a high frequency transformer HFT,
It is equipped with a switching circuit SWC, a rectifier circuit REF, and a counter CNT. switching circuit
The SWC includes an AND gate AG and a transistor TR whose base receives the output of the AND gate AG. The collector of transistor TR is connected to the primary winding of high frequency transformer HFT, and the emitter is grounded. The input of the AND gate AG is a 16Hz ringing ON signal RG from the control unit 44 and a counter.
The 15kHz high frequency signal output from the CNT for the switching regulator is input. counter
For example, the CNT operates based on a 2kHz signal which is a clock signal for the control unit 44 (FIG. 10).
Always feed the above 15kHz signal to AND gate AG. A 24V DC voltage is applied to the primary side of the high frequency transformer HFT.

FIG. 12 is a diagram of voltage waveforms at various parts of the circuit shown in FIG. 11. In the figure, as shown in a and b, the ring-on signal RG (16 Hz) is repeatedly turned on and off at appropriate intervals necessary for ringing the bell of the tone ringer TR under the control of the control section 44. Since a 15kHz signal is always given to the AND gate by the counter CNT, its output is shown in c.
A signal is obtained in which the 16Hz and 15kHz signals are superimposed (Fig. 12d), and this signal causes the transistor TR to
The superimposed signal is applied to the primary side of the high frequency transformer HFT. As a result, the secondary side of the high frequency transformer HFT is supplied with 24V by the action of the switching regulator, which is necessary for ringing a bell, for example.
A 16Hz signal with a peak value converted to 75V is obtained, and the rectifier circuit rectifies the alternating current component of the 16Hz signal to obtain a continuous ringer signal CR at the output. The continuous ringer signal CR is turned on or off by turning on or off the 16Hz ringing on signal RG from the control section 44.

Since the CR signal generating circuit CRG shown in FIG. 11 uses a high frequency transformer, it has the advantage of being extremely compact compared to conventional CR signal generating circuits.

Conventionally, a 16Hz signal is directly converted into a 16Hz continuous ringer signal with a peak value of 75V using a low-frequency transformer.Since the low-frequency transformer is large, the dimensions of the CR signal generation circuit are large, and each subscriber line interface circuit is It was impossible to contain them. Furthermore, in the past, a 16Hz, 75V signal was generated even when the continuous ringer signal CR was turned on and off, and this was switched using other switching means, which caused the problem of high power consumption. .

In contrast, the CR signal generation circuit according to the embodiment of the present invention shown in FIG. 11 can be downsized as described above, and can be housed in the same package as each subscriber line interface circuit. It becomes possible. In addition, the power is turned on by the ringing on signal RG.
Since it also serves as an off switch, power consumption can be reduced.

FIG. 13 is a timing waveform diagram showing the ring trip operation in the circuit of FIG. 10. 1st
In Figure 3, a is a continuous ringer signal CR introduced onto the communication line _L1 , and a direct current is applied to it in the transformer T.
A waveform diagram of a signal on which 24V is superimposed, b is a diagram showing the on/off state of the switch HS ₁ , and c is a waveform diagram of the output voltage of the state detection circuit RT. In the on-hook state where the switch HS ₁ is open, no DC loop is formed in the communication lines L ₁ and L ₂ , so only the 16Hz continuous ringer signal CR is supplied to the communication line L ₂ , and as shown in c, this signal is When the level is high, the photocoupler PC conducts and its output becomes 0V, and when it is low level, the photocoupler PC shuts off and its output becomes the power supply voltage 5V. A state monitoring section (LS) 48 of the control section 44 includes a photocoupler therein.
It has a counter that receives the output of the PC, and this counter is configured so that the output of the photocoupler PC is, for example, 80.
If 0V continues for more than m seconds, a carrier signal is output. Continuous ringer signal CR 1
Since the period is 50 msec, the counter does not output a carrier signal in the on-hook state.

When the hook switch HS ₁ closes at time t and enters the off-hook state as shown in FIG. 13b, the telephone line
A DC loop is formed between L ₁ and L ₂ , and the photocoupler
The PC is always in a conductive state and its output is always 0V. A counter in the control unit 44 outputs a carrier signal when the output of the photocoupler PC counts 0V for 80 msec or more, thereby detecting an off-hook state.

FIG. 14 is a flow chart showing the operation of the sub-controller SUB1 in the circuit of FIG. 2. In FIG. 14, the control unit 44 is initialized in step (91), the timer in the status monitoring unit 48 is set to 5 msec in step (92), the timer is activated in step (93), and the timer is activated in step (94). ) to perform a loop scan of the communication line by the status monitoring unit 48.
This is performed at m second intervals, and in step (95) the ringer sending control unit 46 performs ringer control, and in step 96 it waits until the timer overflows.

FIG. 15 is a flowchart showing step (95) in FIG. 14 in more detail. In Fig. 15, the switch is turned on at step (101).
The state of HS ₁ is detected as described with respect to FIG. If it is in an on-hook state, the hook information is stored in the memory MEM in step (108) and the process returns to the initial stage of the loop scan. If it is in an off-hook state, the off-hook information is stored in the memory MEM in step (102), and it is determined in step (103) whether or not the ringer is ringing. If it is ringing, go to step (104) and connect the relay circuit R of the relevant line (Fig. 10).
is restored, and in step (105) the ringing on signal RG (Fig. 2, 10
The 16 Hz ringer signal is stopped by turning off the 16 Hz ringer signal, and then the dial pulse is detected in step (106). If the ringer is not ringing at step (103), the process immediately moves to step (106). When the dial information is detected in step (106), the detected dial information is stored in the memory MEM in step (107), and the loop scan returns to the initial state again. Even when no dial pulse is detected in step (106), the loop scan returns to its initial state again. A loop scan is performed by repeating the above operation at 5 msec intervals.

FIG. 16 is a flowchart showing step (95) in FIG. 14 in more detail. In FIG. 16, the contents of the memory MEM are read out in step (111), and the read command is analyzed by the command analysis device 45 (FIG. 2) in step (112). If the read command is tone off, turn off the ringing on signal RG in step (115).
Stop the 16Hz ringer signal and step (116)
to restore the relay of the relevant line and end ringer control. If the read command is an extension call or central line call command, turn on the ringer-on signal RG in step (113) to generate a 16Hz ringer signal, and operate the relay circuit of the corresponding line in step (114). This causes the ringer to sound and ends the ringer control.

FIG. 17 is a flowchart showing the operations of writing to and reading from the memory MEM in FIGS. 15 and 16. In FIG. 17, reading/writing to the memory MEM is as follows:
This is done by an external interrupt routine. That is,
Writing to the memory MEM is done by writing to the memory MEM from the buffer memory BM (FIG. 2) in the external interrupt routine 121,
Reading from the memory MEM is done by writing 122 from the memory MEM to the buffer memory in an external interrupt routine.

〔Effect of the invention〕

As explained above, according to the present invention, the main controller can control the two-wire subscriber interface circuit in the same manner as the four-wire subscriber line interface circuit. It is possible to obtain a switching system that can accommodate a mixture of two-wire telephone terminals and four-wire telephone terminals without increasing the burden on the software, and it is possible to reduce the scale of the hardware in the switching system and reduce the cost. It becomes possible.

[Brief explanation of drawings]

FIG. 1 is a block diagram schematically showing a switching system according to the present invention, FIG. 2 is a block circuit diagram showing a two-wire subscriber line interface circuit according to an embodiment of the present invention, and FIG. A block circuit diagram showing a four-wire subscriber line interface circuit according to one embodiment; FIG. 4 is a flowchart showing the originating operation of a two-wire telephone terminal in the circuit shown in FIG. 2;
Figure 5 is a flowchart showing the incoming call operation of the two-wire telephone terminal in the circuit shown in Figure 2, and Figures 6 and 7.
The figures are flowcharts showing the operation of making and receiving calls by the 4-wire telephone terminal in the circuit shown in Fig. 3, Fig. 8 is a diagram showing an example of control information given from the telephone terminal to the main controller, and Fig. 9 is a diagram showing an example of control information given from the main controller to a telephone terminal, Figure 10 is a circuit diagram showing details of the tone ringer TR in the circuit of Figure 2, and Figure 11 is a diagram showing CR signal generation in the circuit of Figure 10. Detailed schematic diagram of the circuit,
Figure 12 is a voltage waveform diagram of each part of the circuit in Figure 11,
13 is a timing waveform diagram showing the operation of the ring trip circuit in the circuit of FIG. 10, FIG. 14 is a flowchart showing the operation flow of the subcontroller in the circuit of FIG.
FIG. 16 is a flowchart showing step (94) in more detail in FIG. 14, and FIG.
FIG. 7 is a flowchart showing the write and read operations for the memory in FIGS. 15 and 16, FIG. 18 is a block circuit diagram showing an example of a conventional switching system accommodating a four-wire telephone terminal, and FIG. FIG. 19 is a block circuit diagram showing an example of a switching system accommodating conventional two-wire telephone terminals and four-wire telephone terminals. 1... Replacement switch, 2... Main control device, 3...
...Memory, 4...Subcontroller, 5...Subcontroller, 8...2-wire telephone terminal, 9...
4-wire telephone terminal, L ₁ , L ₂ ...talk line, L ₃ , L ₄
...control line.

Claims (1)

[Scope of Claims] 1. An exchange switch, a main controller that controls the exchange switch, and a control line that connects a telephone line from a 4-wire telephone terminal to the exchange switch and that controls the exchange of control information. A 4-wire subscriber interface circuit for connecting to the device, a communication line from a 2-wire telephone terminal to the exchange switch, and a control line for exchanging control information to the main controller. and a two-wire subscriber interface circuit, wherein the two-wire subscriber interface circuit converts changes in potential of a communication line connected to the two-wire telephone terminal into digital information and sends the digital information to the main controller. and means for performing ringer control of the two-wire telephone terminal based on digital information from the main controller, and an interface between the main controller, the exchange switch, and a subscriber line interface circuit. An exchange system accommodating 2-wire/4-wire terminals, characterized in that the Ace is the same for both 2-wire and 4-wire telephone terminals.