JPS5813060A - Forcible releasing system for circuit - Google Patents

Abstract

PURPOSE:To forcibly release a trunk line being used for general calling without reference to its connection direction, by providing a means of disconnecting a calling-side trunk from a precedent device once receiving a signal for showing the release of a called subscriber. CONSTITUTION:The switchboards at stations A and B are used for general calling between telephone sets 10 and 20 through both-way trunks 12 and 22 of a calling subscriber control system. The dispatching board 16 equipped at the station A puts a dispatching switching device 13 in operation through a dispatching common device 15 to transfer a switching signal to a switching device 23 to be dispatched through a trunk line 3, and thus a telephone set 24 to be dispatched is called to perform dispatching. In this case, when the trunk line 3 is used for general calling, an added device 25 provided with the both-way trunk 22 discriminates a release signal and performs forcible releasing operation to disconnect the trunk 22 from a precedent device.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a forced line recovery system, particularly a line forced recovery system in a relay line connected to a caller-controlled trunk. A relay telephone network that handles general telephone calls may be accompanied by a command telephone network that handles command anecdotes that are transmitted from a specific command desk to a receiving telephone installed at the above-mentioned outbound station. However, in the command telephone network, it is uneconomical to provide a dedicated command line directly connected to the command desk and each receiving telephone, so the relay lines constituting the relay telephone network are switched and used at the time of command. In many cases, there is a command telephone network that doubles as a trunk line.

In the case of an emergency command, the dual-purpose trunk line is being used by the general public. - In some cases, it may be necessary to temporarily restore the general telephone connection. Figure 1 is a diagram showing an example of this type of conventional crystal-forced recovery system. In Figure 1, the relay 113 installed between stations A and 8 is
is link 11 of the fi island switch located at each station A and B.
and 21 via caller control type two-way trunks 12 and 22, and is used for general communication between the telephones 10 and 20-sized telephones accommodated in the links 11 and 21. The relay 113 is connected to a command console 16 provided at station AK via a command switching device 13, and also connected to station B.
It is connected via an order switching device 23 to an order reception switch 24 provided in the. The command desk 16 is operated by a known method.
The command switching device 13 is activated via the command common device 15, and a switching signal is transmitted to the receiving switching device 23 via the relay Is3 to call the receiving telephone 24. Note that the bidirectional trunks 12 and 13 of the open stations A and B are kept closed to general calls. Relay line 3 is a telephone.

When in use for general calls between 10 and 20,
The command desk 16 activates the forced recovery device 14 to restore the trunk line 3.
try to release it. FIG. 2 is a diagram illustrating the line forced restoration means in FIG. 1. In addition, in Figure 2, both stations A
Only the relevant parts of the bidirectional trunks 12 and 22 at station A and B and the forced recovery device 14 at station A are shown, the others being omitted. Now, if the telephone 10 in FIG. 1 makes a call and the telephone 20 is in an open call, the relay A1 of the two-way trunk 12 in FIG. It operates in a loop of the telephone 10 (not shown) and connects the ground to the signal control terminal DLI through the loop. Furthermore, since relay OG1 (not shown) is operating, relay B1
also operates, connects the earth to the holding line C of the link 11, and maintains the connection path to the telephone 10. In the one-way power direction trunk 22, the relay lI! from the two-way trunk 12!
The relay R2 is operated by the earth air delivered to the signal receiving terminal RG2 via J3 etc., and since the illustrated relay OG2 is in the recovery state, the relay 82 is operated, and the holding # of the link 21 (not illustrated) is activated. A connection path to a telephone 20 (not shown) is maintained. When the telephone 20 is answering, the relay A2 is activated by the loop of the telephone 20 through the link 210 communication lines a and b, connects the ground to the signal control terminal DL2, and activates the relay R1 located in the two-way trunk 12. When a command desk (not shown) activates the forced recovery device 14 for command communication in a state of 0 or \, the cut point t is activated and disconnects the operating circuit of the relay A1 in the bidirectional trunk 12. As a result, the relay AI is restored, the air connected to the signal control terminal DLI is removed, the relay R2 of the bidirectional trunk 22 is restored, and then the relay B2 is restored, and the holding line C of the link 21 is restored.
to telephone 20 of J-link 22, excluding the
(・The connection path is released. Since the relay A2 is also pressed and the earth connected to the signal control terminal DL2 is removed, the relay R1 of the two-way trunk 12 is also restored.

In the two-way trunk 12, the welfare relay B1 is also restored, and the link 12 is
The connection route to the telephone 10 is released. As a result, the three trunk lines currently used for general calls between $10 and $20 are completely released and can be used for command calls. Next, when the telephone 20 makes a call and the telephone 10 is called and is in a busy state, the relay A is connected to the bidirectional trunk 22, contrary to the above.
2, B2, R2 and relay OG2 (not shown) are in operation, and relays AI, B1 are activated in bidirectional trunk 12.
and R1 are operating. In this state, as described above, when the command desk 16 operates the forced recovery device 14 and disconnects the operating circuit of the relay AI in the bidirectional trunk 12,
Relay A1 is restored and the signal connected to the signal control terminal DLI is removed, but in the two-way trunk 22, only relay R2 is restored, and until the calling telephone 20 is restored, bv relays A2 and B2 are removed. does not recover and continues to connect the earth to the signal control terminal DL2, so relays R1 and B1 continue to operate in the two-way trunk 12, so the connection path to links 11 and 21t-j telephone 10 or 20. , and trunk line 3 continues to be occupied. Therefore, there is no other option than to temporarily interrupt the trunk line 3 during a call from the command desk 16 and prompt the calling telephone 20 to recover, or to use the trunk line 3 exclusively for calls from station A.

As is clear from the above explanation, in the conventional forced recovery system, the command desk 16 cannot occupy the relay line 3 for command calls at any time, regardless of whether it is used for general calls. cause trouble. As a countermeasure, it is considered to use the trunk line 3 only in one direction, but this would reduce the usage efficiency of the trunk line and impair the economic efficiency of the trunk telephone network.

The purpose of the present invention is to eliminate the shortcomings of the conventional line forced restoration method as described above, and to realize a means that allows trunk lines used for general calls to be forced to be restored at any time, regardless of the direction in which they are connected. .

The purpose of this is to enable communication between the calling trunk and the preceding device by transmitting a signal indicating that the called party has recovered from the calling trunk on the trunk line connected to the calling trunk. An embodiment of the present invention will now be described with reference to FIGS. 3 and 4. FIG. 3 is a diagram showing a line forced restoration system according to an embodiment of the present invention, and FIG. 4 is a diagram showing an example of the configuration of an additional device in FIG. 3.

Note that the same reference numerals indicate the same objects throughout the figures.

The recovery control scheme for bidirectional trunks 12 and 22 at stations A and B is caller controlled, similar to that shown in FIG. The difference between FIG. 3 and FIG. 1 is that the bidirectional trunk 22 in station B is provided with an additional device 25 for changing the restoration control method. Trunk line 3 is station A
When the telephone is busy for general calls from the calling telephone 10 located at station B to the called telephone 20 located at station B, relay OG2 (not shown) is connected to the two-way trunk 22 in FIG.
is in the recovery state, the communication lines a and b and the holding line C of the additional device 25 are connected to the bidirectional trunk 22.
It becomes an extended period of time. If the command desk 16 operates the forced recovery device 14 at the station A in the still \ state, the trunk line 3 in use is released through the same process as in FIG. Next, when trunk line 3 is heavily used for general calls from calling telephone 20 in station B to called telephone 10 in station A, relay A2 and Relay 0 not shown with B2
Since 02 is also operating, relay MB in additional device 25
At the same time, Relay OG is also located in the operation area. Furthermore, the called telephone 1
When 0 responds, relay 82 of bidirectional trunk 22 is activated, so that relay E in additional device 25 and then EA are activated.

In this state, the command desk 16 at station A is forced to recover □ Device 1'' operation 256 and @ 211K & ff, L, !
: In the process of 1ilil*, the relay R2 of the bidirectional trunk 22 becomes obsolete. As a result, the relay EA in the additional device 25 recovers slowly, and the relay TR
Activate L to disconnect communication lines a and b leading to link 21. Therefore, in the bidirectional trunk 22, relay A
and B are sequentially restored, removing the earth connected to the holding line C of the link 21, and releasing the connection path of the link 22 to the calling telephone 20. The signal control terminal DL2 is then restored. Since the earth connected to the telephone is also removed, the two-way trunk 12 in the central office is also restored.The trunk line 3, which is frequently used for general calls from the calling telephone 20 to the called telephone IO, is also restored. It is completely released and can be used for command calls.

It is clear from the above explanation that according to this example, station B
By providing an additional device 25 on the bidirectional trunk 22 located at
Even when the command desk 16 is busy with general calls leading to By way of example only, e.g. additional equipment 25 and bidirectional trunk 22
The configurations of and 12 are not limited to those shown in the drawings, and many other modifications may be considered, but the effects of the present invention will not change in any case. Furthermore, general calls using the trunk line 3 are not limited to those exchanged between the telephones 10 and 20, and may be made from various call sources; The effect of the invention remains the same.

As described above, according to the present invention, even when a trunk line connected to a caller-controlled trunk is used in any connection direction for general calls, it is possible to forcefully obsolete it at any time.
It can also be used for commands and orders from the command desk without any problems. −

[Brief explanation of drawings]

FIG. 1 is a diagram illustrating an example of a conventional line forced restoration method and an example of an additional equipment layer. In the figure, A and B are stations, IO and 20 are telephones, 11 and 21 are links, 12 and 22 are bidirectional trunks, 13 is a command switching device, 23 is an order receiving switching device, 1
4 is a forced recovery device, 15 is a command common device, 16 is a command console, and 24 is a command receiving telephone. 25 is an additional device, 3 is a trunk line, A1, A2, B1, B2
, R1, R2, MB, 0GXE, EA and TRL are relays, DLI and DL2 are signal control terminals, RGI and RG2 are A and No. 1 receiving terminals, and a and b are communication lines 1.
c indicates a holding line. A 118

Claims (1)

[Claims] In trunk lines connected to caller-controlled trunks,
The calling side trunk 5 is further provided with means for disconnecting the calling side trunk from the preceding device when a signal indicating recovery of the called party is transmitted from the calling side trunk. Line forced recovery method.゛・