JPS6210064B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to forced line recovery schemes, and more particularly to forced line recovery schemes in trunk lines connected to caller controlled trunks.

A relay telephone network that handles general calls between telephones housed in a plurality of telephone exchange offices is attached with a command telephone network that handles command calls transmitted from a specific command desk to receiving telephones installed in the plurality of telephone exchanges. There may be cases where However, in the command telephone network, it is uneconomical to provide a dedicated command line that directly connects the command desk and each command receiving telephone, so the relay lines constituting the relay telephone network may be switched and used at the time of command. Not a few. In the case of a command telephone network that also serves as a trunk line, even if the trunk line is in use for a general call during an emergency command, it is necessary to forcibly restore the general call connection.

FIG. 1 is a diagram showing an example of a conventional line forced restoration method of this kind. In FIG. 1, trunk line 3 between stations A and B is connected via caller-controlled bidirectional trunks 12 and 22 to telephone exchange links 11 and 21 at each station A and B. The telephones 10 and 20 accommodated in the links 11 and 21 are used for general calls. The trunk line 3 is connected to a command desk 16 provided in station A via a command switching device 13, and is also connected to a command receiving telephone set 24 provided in station B via a command switching device 23. There is. The command desk 16 operates the command switching device 13 via the command common device 15 by a known method, transmits a switching signal to the order receiving switching device 23 via the trunk line 3, and calls the receiving telephone 24. Meanwhile, the bidirectional trunks 12 and 13 of stations A and B remain closed to general calls. When the trunk line 3 is in use for general calls between the telephones 10 and 20, the command desk 16 activates the forced recovery device 14 to try to release the trunk line 3. FIG. 2 is a diagram illustrating the line forced restoration means in FIG. 1. In FIG. 2, only the related parts of the bidirectional trunks 12 and 22 in both stations A and B and the forced recovery device 14 in station A are shown, and the rest are omitted. Now, if the telephone 10 in FIG. 1 makes a call and the telephone 20 is called and is in the middle of a call, the relay A1 of the two-way trunk 12 in FIG.
Telephone 10 (not shown) via forced recovery device 14 and communication lines a and b of link 11 (not shown)
It operates by the loop of signal control terminal DL.
It connects earth energy to 1. Additionally, relays not shown
Since OG1 is operating, relay B1 is also operating, connects the earth to the holding line c of link 11, and maintains the connection path to telephone 10. On the other hand, in the two-way trunk 22, the relay R2 is operated by the air delivered from the two-way trunk 12 to the signal receiving terminal RG2 via the trunk line 3, etc., and since the relay OG2 (not shown) is in the recovery state, the relay B
2 operates to connect the earth to the holding line c of the link 21 (not shown) and maintain the connection path to the telephone 20 (not shown). Link 2 while telephone 20 is answering
Relay A2 is operated by the loop of telephone 20 through communication lines a and b of 1, and signal control terminal DL is activated.
2 and activate the relay R1 in the bidirectional trunk 12. When a command desk (not shown) activates the forced recovery device 14 for command communication in such a state, the cut point t is activated and the bidirectional trunk 12 is activated.
Disconnect the operating circuit of relay A1 located at. As a result, relay A1 is restored, the earth connected to signal control terminal DL1 is removed, relay R2 of bidirectional trunk 22, and then relay B2 is restored, and earth air connected to link 21's holding line c is removed. link 22 phone 2
Release the connection path leading to 0. Also relay A2
Since the relay R1 of the two-way trunk 12 is also restored, the relay R1 of the two-way trunk 12 is also restored. In bidirectional trunk 12, relay B
1 is also restored, the earth connected to the holding line c of the link 11 is removed, and the connection path of the link 12 to the telephone 10 is released. As a result of the above, telephones 10 and 2
The trunk line 3, which is currently being used for general calls between 0 and 0, is completely released and can be used for command calls. Next, phone 2
0 makes a call and the telephone 10 is called and is in the middle of a call.Contrary to the above, relays A2, B2, R2 and a relay (not shown) are activated in the bidirectional trunk 22.
OG2 is active and relays A1, B1 and R1 are active on bidirectional trunk 12. In such a state, the command desk 16 operates the forced recovery device 14, as described above, and the bidirectional trunk 12
When the operating circuit of relay A1 in the trunk 22 is disconnected, relay A1 is restored and the earth connected to signal control terminal DL1 is removed, but in the two-way trunk 22, only relay R2 is restored, and the calling telephone Relays A2 and B2 will not be restored unless 20 is restored and will continue to connect the ground to signal control terminal DL2, so relays R1 and B1 will continue to operate even in bidirectional trunk 12, so links 11 and 21 will be connected to telephone 10. Alternatively, the connection route to 20 is maintained, and the trunk line 3 continues to be occupied. Therefore, the command console 16 temporarily interrupts the trunk line 3 during the call and prompts the calling telephone 20 to recover, or
Alternatively, there was no other option than to use trunk line 3 exclusively for calls from station A.

As is clear from the above explanation, in the conventional line forced restoration method, the command desk 16 is unable to occupy the relay line 3 for command calls at any time, regardless of whether it is used for general calls, and this may interfere with command calls. Come. 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.

An object of the present invention is to eliminate the drawbacks of the conventional line forced recovery system as described above, and to realize a means by which a trunk line used for general calls can be forcedly recovered at any time, regardless of its connection direction.

The purpose of this is to connect the calling trunk to 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. This is accomplished by adding means to the calling trunk to disconnect the caller.

An embodiment of the present invention will be described below 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.
Bidirectional trunks 12 and 2 at stations A and B
The recovery control method No. 2 is a caller control method 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. When the trunk line 3 is in use for general calls from the calling telephone 10 at station A to the called telephone 20 at station B, the relay OG (not shown) is connected to the bidirectional trunk 22 in FIG.
2 is in the recovery state, only the relay MB operates within the additional device 25, and the communication lines a and b and the holding line c of the link 21 (not shown) are extended to the bidirectional trunk 22. In addition, if the command desk 16 operates the forced recovery device 14 at station A in such a state, the trunk line 3 in use
is released in a process similar to that in FIG. Next, the trunk line 3 connects the calling telephone 20 located at the station B to the station A.
When the telephone is in use for general calls to the called telephone 10 located in the two-way trunk 2 in FIG.
2, the relay OG2 (not shown) is also operating together with the relays A2 and B2, so the relay OG as well as the relay MB in the additional device 25 are in the operating state. Furthermore, when the called telephone 10 answers, relay R2 of the two-way trunk 22 is activated, so that relay E in the additional device 25 and subsequently EA are activated.
When the command desk 16 operates the forced recovery device 14 at station A in such a state, the relay R2 of the two-way trunk 22 is restored in the same process as shown in FIG. As a result, relay EA in additional device 25 recovers late, operates relay TRL, and disconnects telephone sets a and b connected to link 21. Therefore, in the two-way trunk 22, relays A and B are sequentially restored, the connection path connected to the holding line c of the link 21 is removed, and the connection path of the link 22 to the calling telephone 20 is released. Moreover, since the earth connected to the signal control terminal DL2 is also removed by the restoration of the relay A2, the bidirectional trunk 12 in the station A is also restored.
As described above, the trunk line 3 which is in use due to the general call from the calling telephone set 20 to the called telephone set 10 is completely released, and can be used for command calls.

As is clear from the above description, according to this embodiment, the additional device 2 is connected to the bidirectional trunk 22 in station B.
5, the trunk line 3 connects to the calling telephone 2.
0 to the called telephone 10, the command console 16 can be forced to recover by operating the forced recovery device 14.

Note that FIGS. 3 and 4 are only one embodiment of the present invention, and the configurations of the additional device 25 and the two-way trunks 22 and 12 are not limited to those shown in the figures, and there may be many other configurations. However, the effects of the present invention do 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 if the trunk line connected to the caller-controlled trunk is used in any connection direction for general calls, it is possible to forcefully restore the line at any time, and the command call from the command center It can also be used for both purposes without any problem.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of a conventional line forced restoration method, FIG. 2 is a diagram illustrating the forced restoration means in FIG. 1, and FIG. 3 is a diagram showing a line forced restoration method according to an embodiment of the present invention. , FIG. 4 is a diagram showing an example of the configuration of the additional device in FIG. 3. In the figure, A and B are stations, 10 and 20
is a telephone, 11 and 21 are links, 12 and 22 are bidirectional trunks, 13 is a command switching device, 2
3 is a command switching device, 14 is a forced recovery device, 15 is a command common device, 16 is a command console, 24 is a command receiving telephone, 25 is an additional device, 3 is a trunk line, A1, A2,
B1, B2, R1, R2, MB, OG, E, EA and TRL are relays, DL1 and DL2 are signal control terminals, RG1 and RG2 are signal receiving terminals, a and b are communication lines, and c is a holding line. .

Claims (1)

[Claims] 1. Means for cutting off the connection between the calling trunk and the preceding device by transmitting a signal from the calling trunk indicating that the called party has recovered, in a trunk line connected to the calling trunk. A line forced recovery method characterized in that a line is added to the calling side trunk.