JPS63233646A - System for forming speech path in inter-private branch exchange - Google Patents

Abstract

PURPOSE:To eliminate the need of a specified circuit, compared with a system in which an OD trunk or an LD trunk is used, by connecting between private branch exchanges PBX by using an ordinary line circuit and a central office bidirectional trunk. CONSTITUTION:The line circuit 4 of first PBX1 is connected to the central office bidirectional trunk of second PBX2 with an exclusive line 7, and when the outgoing from the extension telephone set 8 of the second PBX2 to the first PBX1 is issued, an extension is selected by sending a selection signal after a DC loop is generated. Meanwhile, when the outgoing from the extension telephone set 6 of the first PBX1 to the second PBX2 is issued, a ringing signal is sent, and an opposite set receives the signal, and after the generation of the DC loop being confirmed, the selection signal is sent, then, the extension is selected. In such a way, it is possible to connect directly between the PBXs without using a specified housing trunk for the exclusive line.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for forming communication paths between a plurality of private telephone exchanges.

Conventionally, in the private telephone exchange equipment (hereinafter referred to as PBX),
There is a considerable demand for direct connection between multiple PBXs. In order to meet these demands, conventionally, the connection between PBXs was
There are those that use D-trunk and connect with a dedicated long-distance line, and those that use LD) rank and connect with a local dedicated line.

However, when using a 0DI-rank or LD trunk, it is a special circuit, which is not desirable from a cost performance standpoint, and there is a desire to do without it if possible.

In view of these points, it is an object of the present invention to provide a new method for directly connecting PBXs without using special dedicated line accommodation trunks.

In order to achieve the above-mentioned object of ``mu'', the present invention connects the line circuit of a first PBX and the central office line bidirectional trunk of a second PBX with a dedicated line, and connects the extension telephone of the second PBX. 1st PBX from
When making a call to a second PBX, a DC loop is created and a selection signal is sent to select the extension; on the other hand, when making a call from the extension telephone of the first PBX to a second PBX, a ringing signal is sent to select the other party. The feature is that after confirming that the machine receives this and creates a DC loop, it sends a selection signal and selects the extension line.

The operation of the present invention will be explained in detail in Examples.

Figure 1 is a connection configuration diagram showing an embodiment of the present invention.
．． 2 is a PBX, 3 is a bidirectional trunk for accommodating an office line, and 4 is a line circuit for accommodating an extension 5 or 6. One PBX 1's central office line bidirectional trunk 3 and the other PBX 2
It is directly connected to the line circuit 4 by a dedicated line 7.

In this case, by simply connecting the PBX 10 bidirectional trunk 3' of one PBX and the line circuit 4 of the other PBX 2, it is possible to select the extension of PBX 2 by making a call from the PBXI, but conversely, the PBX 2 It is not possible to select the PBXI extension depending on the call originating from. That is,
PBX2 will give a ringing signal to PBXI, but if you just send a ringing signal, the PBX
Even if PBX 1 knows that there is an incoming call, PBX 1
It is not known which extension will be selected.

This is similar to the fact that, in general, when connecting a PBXO office line trunk to a subscriber circuit of a public telephone network, an extension cannot be selected even if a ringing signal is sent from the public network side.

Therefore, in the present invention, the following call control is performed so that the other extension can be selected from any PBX. First, the PBX 2 connected to the dedicated line 7 through the line circuit 4 is designated as A, the PBXl connected to the dedicated line 7 through the office line bidirectional trunk 3 is designated as B, and a call is made from extension 4 of B to extension 5 of A. The case of forming a road will be explained. In this case, the processing proceeds in the following order.

■When extension 5 is on-hook, B closes the DC loop. At this time, if A has a line polarity reversal function, it performs reversal.

(2) After B detects this, it issues a selection signal from extension 5. If A does not have an inversion function, B will issue a selection signal after a certain period of time.

(2) Thereafter, A selects a specific telephone extension from among his/her own telephone extensions according to the selection signal, and connects the telephone line. During that time, the calling party's extension is listening to the ring bank tone from A.

■Once the communication path is established, a conversation will take place between the two parties.

■Once the conversation is over, recovery is achieved by opening the DC loop from B. In this case, even if A side's extension is on-hook, B
The DC loop is opened when B's extension goes on-hook.

Next, when A's extension 6 makes a call and forms a communication path with B's extension 5, the following operations are performed in the order of 0 to [phase].

■Inside! v! When 6 goes on hook, B detects it and
Send dial tone to extension 6.

(2) When the extension 6 dials a special number, for example "8", to designate A, A detects this and detects one of its own line circuits 4 that is connected to B and is available.

■Then, a calling signal is sent from 8 to the B side.

(2) Based on this, the B side determines that there is an incoming call, and closes the DC loop as a - next response signal.

0 Next, when the number of the desired extension 5 on the B side is dialed using the extension 6 on the A side, the selection signal is sent to the line circuit 4,
It is sent to B through the dedicated vA 7 and the central office line bidirectional trunk 3.

[Phase] When the B side receives this selection signal, it opens the DC loop in response. At this time, the A side sends a ringing tone (ring bank tone) to the extension 6 that issued the selection signal.

On the other hand, the B side checks whether the extension 5 indicated by the selection signal is busy or absent.

[Phase] If extension 5 is not busy or absent, when off-hook, B receives the response signal and closes the DC loop again (secondary response).

[Phase] When A receives the secondary response, it learns that the target extension 5 has been connected, and forms a communication path with the extension 5 that made the call. In this way, extensions 5 and 6 can converse with each other.
4 [Phase] Once the conversation is finished, recovery is achieved by opening the DC loop on the B side. FIG. 2 shows, in chronological order, the signal transmission and reception from the call originating from extension A to the communication with extension B, as described above.

As described above, by using a line circuit and a bidirectional office line trunk, two PBXs can be directly connected, and moreover, it is possible to make calls with selection signals from both directions, which can be said to have great advantages.

DETAILED DESCRIPTION OF THE INVENTION As described in detail, according to the present invention, connections between PBXs can be made by using normal line circuits and central office line bidirectional trunks. Compared to this, no special circuit is required, which is very advantageous in terms of cost performance.

Furthermore, the connection using the line circuit for accommodating extension lines and the central line bidirectional trunk for accommodating central office lines as in the present invention facilitates the flexibility of the accommodating circuits, resulting in an efficient system configuration.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram showing an embodiment of the present invention, Fig. 2 is I)
FIG. 3 is a diagram illustrating signal exchange between B and X. ■, 2...Private telephone exchange, 3...Directory line bidirectional trunk, 4...Line circuit, 5.6...Extension line, 7.
・Dedicated line.

Claims (1)

[Claims] Connecting the line circuit of the first private telephone exchange and the central office line bidirectional trunk of the second private telephone exchange by a dedicated line,
When making a call from the extension telephone of the second private branch telephone exchange to the first private branch telephone exchange, after creating a DC loop,
A selection signal is sent to select an extension; on the other hand, when a call is made from the extension telephone of the first private branch exchange to a second private branch exchange, a ringing signal is sent and the other party receives it and starts a DC loop. A method for forming a communication path between private branch telephone exchanges, characterized in that after confirming that an extension has been created, a selection signal is sent to select an extension.