JPS647714B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a camp-on connection control system, and more particularly to a control system for limiting the multiplicity of camp-on connections in a common control automatic switching system.

Common control automatic exchanges, especially private branch exchanges, may provide camp-on service. Camp-on service refers to the caller's status when the called party is busy, when the caller or attendant operates the camp-on operation, and the caller's status is monitored automatically when the callee is free. A service that calls the called party and connects them to the calling party, and is generally used for intra-office intercommunication and central office line incoming calls.

Next, problems with the conventional camp-on-service system will be explained.

Figure 1 shows the camp-on mode for incoming calls on the central office line.
1 is a connection diagram of an example of a conventional private branch exchange capable of providing services; FIG. In the figure, EX is an extension telephone,
LLF is the communication path network, MKR is the common control device,
COTA and COTB are central office line trunks, each of which has a camp-on device added to provide camp-on service for normal trunk circuits, and ATT is a relay stand and CDL.
is a code link for connecting the office line trunks COTA, COTB and the relay stand ATT, and is controlled by a code link controller (not shown).

Now, for example, the extension telephone EX is connected to the central office line via the route of the central office trunk COTA and the communication network LLF, and in this state, the extension telephone EX is connected to the central office line via the central office line trunk COTB.
Suppose that EX receives a call. Then, as is well known, the central office line trunk COTB is a code link.
It is connected to the attendant ATT via the CDL, and the attendant responds by sending the number of the called extension telephone from the attendant ATT to the common control device MKR.
Normally, the common control unit MKR identifies that the called extension is busy and sends a busy signal to the attendant ATT to abandon the call. However, if the operator of the relay console turns on the camp by operating the camp-on button on the relay console ATT, etc. (depending on the exchange, the camp-on state will be activated immediately without the need to operate the button). (In some cases, the button is operated only to release the button.) Common control device
The MKR connects the office line trunk COTB to the telephone EX in use via the path of the communication network LLF, and also sends busy information to the office line trunk COTB and relay stand ATT. The office line trunk COTB receives the busy information and enters the monitoring state of the called telephone EX. The relay console is released from the above connection by code link CDL restoration and can perform other processing. At this time, the communication path is of course maintained.

When the call through the above communication path ends and the connection between the called telephone EX and the office line trunk COTA is released, the office line trunk COTB that was previously connected via camp-on detects this and A calling signal is sent from the office line trunk COTB to call the called extension telephone EX via the route. When the called extension telephone EX answers, since the telephone EX is connected to the central office trunk COTB by the route,
A call can be made to the waiting caller via the central office trunk COTB.

FIG. 2 is a diagram mainly showing the connection of central office line trunks COTA and COTB capable of camp-on service. In the figure, the central office line trunk COTA
and COTB have the same configuration, but COTB
Only some details are shown. In the figure, A is a relay that supplies talking current to the extension telephone (EX) and monitors its loop status, and bt ⁰ and bt ¹ are camp relays.
This is the contact point of relay BT for creating a circuit that monitors the idle state of the extension telephone when it is in the on state, but its winding is omitted from the diagram. SP is a relay that monitors the idle state of the captured telephone by the camp-on connection, and has a high resistance winding, and INT is a disconnection relay that operates at fixed time intervals. Other symbols indicate the same as in FIG.

As mentioned above, the extension telephone EX is connected to the call route network.
Assume that the LLF route connects to the central office line trunk COTA and that a call is being made to the central office line. central office trunk
Since COTA is not camped on, relay BT (not shown) is in the recovery state, with its contacts bt ⁰ and bt ¹ in the positions shown, and relay A has ground, winding I, contacts bt ⁰ , route and extension
It operates through the EX loop, contact bt ¹ , and winding 1, and supplies talking current to the extension telephone EX and monitors its loop status.

As already mentioned, the camp-on operation is performed at the relay stand ATT, so when an incoming call is received to the extension telephone EX via the central office line trunk COTB, the central office line COTB is routed to the extension telephone EX.
It is connected to EX and receives busy information from common control device MKR. When this busy information is received, relay BT (not shown) operates and contacts bt ⁰ ,
Convert bt ¹ . This connects the high resistance relay SP to the communication line and activates it. That is, in this case,
Office line trunk COTB ground, contact int, relay
SP, diode D ₁ , contact bt ¹ , and communication network
One side of each talk line and central office line trunk COTA contact point bt ¹ (normal state), with LLF path
A circuit is created from the winding of relay A to the (-power supply), and the relay SP of the office line trunk COTB operates in the above circuit. Furthermore, when the call ends and the phone is turned on at the extension telephone EX, relay A, which is activated by the loop of the extension telephone EX, is restored on the central office trunk COTA, and the central office trunk COTA is released, and the telephone trunk COTA is released. The communication path will also be freed up. Therefore, the above circuit is also disconnected, and the relay SP of the office line trunk COTB is also restored. That is,
In the trunk running the camp-on service, in this case the office line trunk COTB, the idle state of the extension telephone EX is monitored by its relay SP.

When the relay SP recovers and identifies that the extension telephone EX that is in camp-on is now available, the trunk on which the camp-on service is being performed, in this case the office line trunk COTB, is connected to the extension via a known means (not shown). Sends a call signal to telephone EX. When the extension telephone EX answers, it stops sending out the ringing signal, and the relay A operates in the same manner as described above, making it possible to talk to the waiting caller via this office line trunk COTB.

The camp-on service for incoming calls to the central office line has been described above, but the camp-on service is also possible for inter-extension calls. That is, when an extension telephone calls another extension telephone, the caller hears the busy tone and learns that the called party is busy, and then dials a special number to request camp-on service. The common control unit MKR learns of the camp-on service request from the special number and connects the called party and the calling party via an intraoffice trunk capable of camp-on service. This intra-office trunk is the office line trunk shown in Figure 2.
Similar to COTA and COTB, normal intra-office trunks can be modified to enable camp-on service. Note that the steps after the above connection are the same as those for the central office line trunk, so the explanation will be omitted.

Conventionally, camp-on service was implemented as described above, so it was possible to connect multiple camp-on connections to a single called party from a trunk capable of camp-on service to any number of lines. It was inevitable that it would happen.

When such multiple camp-on connections occur, when the called party ends the call, the order in which many waiting trunks are called is determined by the priority chain and the connection position of the trunks. A caller connected to a lower priority trunk must wait until all callers connected to a higher priority trunk have finished their calls. This often results in customers having to wait for long periods of time and not being able to enjoy the benefits of camp-on service.

Furthermore, when the above-mentioned multiple camp-on connections occur, all the called party occupancy monitoring relays SP of the trunks that are camp-on connected to one telephone are connected in parallel, and the A relay of the busy trunk is connected in parallel. It will be connected to. Therefore, even if the relay SP has a high resistance, many relays are connected in parallel, so even if the called party becomes unavailable and the loop is broken, the relay A of the trunk used for the call may become unrecoverable and become permanently retained. be. Note that unless relay A is restored, the trunk used for the call will not be released.
Also, because of this, it is not possible to identify that the called party is free on the trunk connected to camp-on.
Camp-on-service becomes impossible.

In order to prevent the above-mentioned A relay of the trunk used for calls from being permanently held, in the conventional camp-on-service trunk, a disconnection relay is used as shown in Figure 2 for the office line trunk COTB.
INT is installed and its disconnection relay is applied to all camp-on-serviceable trunks within the station.
All INTs were temporarily activated at a certain period, for example, 10 seconds, and the contact INT was opened to cut off the earth's air to the relay SP, temporarily restoring the relay SP, and temporarily cutting off the permanent holding circuit for the relay A.

Now, as shown in Figure 2, the extension telephone EX is
It is assumed that the extension telephone EX is connected via the central office line trunk COTA and the communication path of the communication network LLF, and the above extension telephone EX is in a multiple camp-on state due to multiple trunks capable of camp-on service. It is assumed that it is familiar. The plurality of trunks include, for example, a central office line trunk COTB.

The disconnection relay INT operates simultaneously on a trunk connected to one extension telephone EX and on multiple trunks connected with camp-on, but in each trunk connected with camp-on, Contacts int open relay SP and call connected trunk (COTA)
The circuit to the relay A winding is cut off and each relay SP recovers, but relay A of the trunk connected to the call (COTA) continues to operate due to the loop formed by the extension telephone EX and the communication path and does not recover. .

When extension telephone EX is free, if all the disconnection relays INT of each trunk operate at the same time in the same way as above, the contact INT opens in each of the above trunks for camp-on connection, and relay SP and call connection are established (COTA ) circuit for relay A winding (this circuit may serve as a permanent holding circuit for relay A) is cut off, and extension telephone EX is turned on.
Since it is a hook, the extension telephone EX to relay A of the trunk COTA connected to the call and the loop passing through the call path are cut off.
Relay A is restored. The trunk COTA that was connected to the call is restored and the call path is released by the recovery of its relay A.

Therefore, the disconnection relay INT is restored in each trunk (COTB, etc.) connected to camp-on, and
Even if contact int is closed, the communication path is open, so the operating circuit for relay SP and relay A of trunk COTA connected for communication is not configured, and neither of them operates.

When the disconnection relay INT is activated in this way, if the called party (extension phone EX) is empty, the relay SP of each trunk will be restored, and the relay A will be permanently maintained on the trunk used to connect the call. Therefore, when the disconnection relay INT is restored and the contact point int is closed again, the relay SP does not operate in each trunk. In addition, if the called party (extension phone EX) is blocked, when contact int opens, relay A of the trunk (COTA) used to connect the call will not be restored, and therefore the trunk (COTA) will also be connected to the call path. is not released, so the disconnection relay INT is restored and when the contact int closes again, the relay SP operates again.

In this way, when the disconnection relay INT is temporarily activated, the camp-on connected trunk identifies whether the called party is idle or not depending on whether the relay SP operates again or not. For this reason, it was necessary to provide a disconnection relay INT for each camp-on-serviceable trunk.

In the conventional camp-on service described above, when there are many callers requesting camp-on service to one called party at the same time, the present invention limits the number of callers and only calls some of them. To provide a camp-on connection control system that can prevent a caller from being forced to wait for a long time and achieve this economically.

In the present invention, the drawbacks of the above conventional method are
In view of the fact that multiplexed camp-on connections occur from many trunks, the multiplicity of camp-on connections is limited to a small number.

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 3 is a connection diagram of one embodiment of the present invention. In the figure, LLF indicates a communication path network, and the primary switch stage PSW consists of 10 10×10 primary switches P ₀ to _{P 9}
The secondary switch stage SSW has 10 pieces of 10
It has ×10 secondary switches S ₀ -S ₉ , and each primary switch P ₀ -P ₉ is connected to each secondary switch S ₀ -S ₉ by 10 links, respectively. Secondary switch
The egress sides of S ₀ to S ₉ are dually connected, and some of them are trunks that can be camped on service.
Connected to COTA~COTN. Primary switch P ₀
The output side of ~ _P9 is connected to a telephone (EX, etc.). The switches P ₀ -P ₉ and S ₀ -S ₉ are connected by links consisting of three lines (communication lines a, b and control line C), but only the control line C is shown in the figure. As is well known, when the link is free, there is no potential on the control line C, but when it is blocked, the control line C is given an electric potential. In addition, each channel is connected to each of the 10 links connected to each of the secondary switches S ₀ to S ₉ .
It is assumed that CH ₀ to CH ₉ are configured.

MKR indicates a common control unit, but the figure only shows the part that tests and selects vacant channels. In addition, the contact of is the called party busy identification relay.
It is a contact point of OF, and when the called party is not available, the relay OF is inactive and occupies the position shown in the diagram.
When the called party is busy, the relay OF operates and the contact of
is converted.

Now, for example, trunk COTA and extension phone
When connecting EX, the common control device MKR selects an empty link between the two. First, close all contacts mc (marker connectors) and draw the control lines of all links to the common control device MKR. called telephone
The switch where EX is housed (primary switch)
_P9 ) Based on the information, operate the primary switch designated relay HG9 corresponding to the switch _P9 and close the contact _hg9.
Close. This contact hg ₉ is provided for all channel empty test relays CHT ₀ to CHT ₉ , for example, channel CH0 (secondary switch S ₀
In a channel consisting of links to primary switches P ₀ to P ₉ ), if the link to primary switch P ₉ is blocked, there will be an air flow in the control line of the link between switches P ₉ and S ₀ . Because there is, this ground air is a contact point.
It is given to the channel free test relay CHT0 via hg ₉ , and this relay operates, but when the channel is free, the above link is not connected to the ground, so the above relay CHT0 does not operate. Since channel free test relays CHT0 to CHT9 are provided for each channel CH0 to CH9 as described above, in the same manner as above, a desired free link, that is, a free link leading to switch _P9 ,
A test of all channels having the following conditions (channel vacancy test) is performed.

For example, in the above, channel CH0
In this case, the link between switch P ₉ and S ₀ is blocked,
In channel CH1, if the link between switches P ₉ and S ₁ is free, the channel free test relay CHT
0 is working and CHT1 is also not working, so
Air is applied to channel selection relay CH1 via contacts of (inactive when called extension telephone EX is idle), cht ₀ (active), and cht ₁ (inactive), and this relay CH1 is activated. However, even if the link leading to switch P ₉ in the outer channel is vacant, contact cht ₁ is inoperative, so the other channel selection relays CH ₂ to _{CH 9} do not have operational circuits and do not operate.

Here, by the operation of relay HG9 (not shown) and channel selection relay CH1, the secondary switch is selected in channel CH1.
Among the links originating from _S1 , a link leading to primary switch _P9 (corresponding to relay HG9) is selected, and the office line trunk COTA and the extension telephone are connected via this link. In this case, it is a normal connection and not a camp-on connection, so the relay of the trunk
BT doesn't work.

Connection when performing camp-on service is performed as follows. Assume that the extension telephone EX is busy. In this case, use a camp-on-service trunk, such as a central office trunk.
Assume that a camp-on connection request is made to the extension telephone EX in response to an incoming call to COTA.

In other words, as shown in Figure 1, the central office line trunk
When a call arrives at COTA, the extension trunk COTA is connected to the attendant ATT via the code link CDL, and the attendant responds by sending the number of the called extension from the attendant ATT to the common controller MKR. Send. As is well known, the common control unit MKR is
First, a busy test is performed on the called extension telephone using the above number, but since the called telephone EX is busy at this time, the common control device MKR detects that it is busy.

In this case, since the camp-on operation is performed from the attendant stand ATT, the common control device MKR detects that the called telephone EX is busy, and even if the relay OF is activated, the connection between the trunk COTA and the telephone EX is maintained. control. This connection control is performed by selecting a vacant link in the same way as for the normal connection described above, but in the case of a camp-on connection, the relay OF operates while the called telephone EX is busy, and its contact OF is switched. In the channel selection circuit composed of channel selection relays CH0 to CH9, the operation circuit for channel selection relays CH0 to CH7 is not configured, and the channel selection relays CH8 and CH
Two operation circuits No. 9 are prepared. Therefore, in case of camp-on connection, channels CH8 and
CH9, that is, the channel having the vacant desired link is selected from among the limited two channels. Already channel CH8 and
In CH9, if both desired links are blocked, camp-on connection is not performed. Thus, the number of camp-on connections to one phone is limited to two at most. In the above, if the desired links in channels CH8 and CH9 are both in use, air is sent to point B via contacts of, cht ₈ and cht ₉ , link busy is displayed, and no connection is made.

In this embodiment, camp-on connections are allowed up to a maximum of double connections, but triple or more connections are not allowed. In this way, the camp
By limiting the multiplicity of on-connections to a small number,
The drawbacks of conventional methods are overcome.

The present invention is not limited to the above embodiments, and various modifications can be made within the technical scope.

In the above embodiment, the communication path network has a two-stage configuration of a primary switch and a secondary switch, but it can also be implemented in a multi-stage configuration with an even larger number of stages. Camp-on service can be provided for internal calls using intra-office trunks configured to enable camp-on service.

The present invention can also be implemented in a switch having a common control device under program control.

The present invention is configured as described above, and the number of multiple camp-on connections to one telephone is limited to a small number, so that when there are many callers requesting camp-on service as in the conventional system, This has the effect of eliminating the disadvantage of making some callers wait for a long time, making it virtually impossible to meet the purpose of the camp-on service. In addition, since the number of multiple connections is limited to a small number, the disconnection relay (relay INT) that was previously required for camp-on trunks is no longer required, and a means for periodically operating this is also no longer required, making the configuration easier. It has the effect of being simple and economical.

[Brief explanation of drawings]

Figure 1 is a connection diagram of an example of a conventional exchange capable of camp-on service, and Figure 2 is a diagram of a conventional exchange capable of camp-on service.
FIG. 3 is a diagram illustrating a connection configuration of trunks capable of on-service. FIG. 3 is a connection configuration diagram of an example of a communication path network and a common control device of an exchange implementing the present invention. EX...Extension telephone, LLF...Call network,
COTA, COTB...Central line trunk capable of camp-on service, MKR...Common control equipment,
ATT...Attack stand, CDL...Code link, A
...Loop monitoring relay, SP extension telephone occupancy monitoring relay, INT...Disconnection relay, _P0 to _P9 ...Primary switch, _S0 to _S9 ...Secondary switch, mc...Marker connector, hg ₁ to hg ₉ ...Contact points of primary switch designation relay, CHT ₀ to CHT ₉ ...Channel vacant test relay, CH0 to CH9...Channel selection relay, of...Contact point of subscriber busy identification relay.

Claims (1)

[Claims] 1. A plurality of trunks capable of camp-on service, a communication path network connecting the plurality of trunks and the telephone, and a connection between the telephone and the trunk via the communication path network. In an exchange equipped with a common control device for controlling the telephone set, the common control device controls a channel selection relay for selecting a channel having a vacant link in the communication path network connecting the plurality of trunks and the telephone set. When connecting an incoming call from the trunk to the telephone set, if the incoming telephone set is free, all the channel selection relays are enabled and a free link is selected from all channels in the communication route network. Select a channel with
When performing camp-on service to a terminating telephone when the terminating telephone is busy, only a few specific ones of the channel selection relays mentioned above can be operated, Selecting a channel having a free link from among a limited number of specific channels corresponding to a small number of enabled specific channel selection relays and connecting the channel between the terminating telephone and the camp-on-serviceable trunk. A camp-on connection control method characterized by configuring a communication path.