JPH01293097A - Subrate communication system - Google Patents

Abstract

PURPOSE:To efficiently pass a call at low speed without increasing memory capacity by transmitting a multiplex display bit at low speed to a signal network by attaching on a connection signal at the time of multiplexing the call by a multiplex conversion device. CONSTITUTION:At the time of multiplexing the call from a low speed terminal 7 in a subscriber time divisional exchange LS1 by the multiplex conversion device MUX13, a vacant low speed channel is hunted when the the number in use of a low speed channel is set at 0, and the state of the low speed channel is set at a state in use. The number in use of the low speed channel is increased by 1. Editing is performed by attaching low speed channel display representing the fact that the low speed channel is multiplexed and channel non-setting display meaning the first usage of the Iow speed channel in channels at an output side on a call issuing signal to perform call issuing to a relay time divisional exchange TS2, and the TS2 is started up by sending a result of editing to a common line signal network CSNW3. In such a way, it is possible to pass the call at low speed without increasing the memory capacity.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a subrate communication system, and particularly to a subrate communication system in a time division switching system.

[Conventional technology]

Conventionally, when exchanging calls with a bit rate lower than the switching speed of the exchange in a time division switching system, the first method is to convert the low bit rate to match the switching speed even if the call is low speed. Alternatively, a second method was adopted in which multiple connections were made for calls with high bit rates while adjusting the switching unit to low speed.

[Problem to be solved by the invention]

The first conventional method described above has the disadvantage that the usage rate of the communication channel is low, and the second method has the disadvantage that the switching operation is complicated and the amount of memory of the time division switch is large.

SUMMARY OF THE INVENTION An object of the present invention is to provide a subrate communication system that efficiently switches low-speed calls without changing the switching speed of the main body of the relay time division switch.

[Means to solve the problem]

The subrate communication system of the present invention provides a time division switching system comprising a subscriber time division exchange, a relay time division exchange, and a signal network for transmitting and receiving connection signals between these two exchanges. The exchange includes a low-speed time switch that accommodates low-speed terminals, and a multiplex converter that multiplexes calls on the same route among calls exchanged by the low-speed time switch and sends the multiplexed calls to the relay time division switch. is characterized in that when the call is multiplexed, a low-speed multiplex indication bit is added to the connection signal and transmitted to the signal network.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram of a time division switching system showing an embodiment of the subrate communication method of the present invention, FIG. 2 is a diagram showing an example of a pattern in which a low-speed channel is multiplexed on the speech channel in FIG. 1, and FIG. FIG. 2 is a flow diagram showing a call processing flow of a low-speed call in the subscriber time-division exchange in FIG. 1;

In FIG. 1, the time division switching system is a subscriber time division switching system (hereinafter referred to as LS) that accommodates a telephone terminal 6 and a low speed terminal 7.
) 1, a relay time division switch (hereinafter referred to as TS) 2 connected to this via a relay transmission line 4.5, and a common line signal network (C3NW) that is interposed between the LSI and 732 to transmit and receive connection signals.
It is composed of 3. The LSI is connected to a telephone line time switch (hereinafter referred to as TDt) 11 that accommodates the telephone terminal 6, a low-speed line time switch (hereinafter referred to as TDo) 12 that accommodates the low-speed terminal 7, and the TDD 12, and are connected to the same route. A multiplex converter (hereinafter referred to as MU) that multiplexes calls
X) 13.

Note that, to simplify the explanation, the exchange speed of TDT II is assumed to be 64 Kbps, and the exchange rate of TDD 12 is assumed to be 8 Kbps. Further, the LSI and TS2 are each program-controlled by a central control unit (not shown). Relay transmission line 4
．． 5 and TS2 are based on telephone lines, and the communication channel is 64 Kbps. On the other hand, subscribers with low-speed terminals are connected to TDo12, and MUX13
The signal is multiplexed into 64 Kbps and sent to the relay transmission line 5. In FIG. 2, which illustrates this multiplexing, 20 indicates the arrangement of communication channels for the telephone line on the relay transmission path, and 21 indicates one channel C for the telephone line.
H↑ shows that low-speed channels are multiplexed. In this example, the slow channel is 8Kbps
Therefore, 8 signals are multiplexed.

Next, the switching operation of this low-speed channel as a network will be explained.

As mentioned above, the switching speed of TS2 is 64 Kbps since it is based on a telephone line, and call routing is also performed in this unit.

Therefore, when multiplexing calls from the low-speed terminal 7 of the LSI using the MUX 13, a method is used in which calls on the same route are multiplexed. As shown in FIG. 3, in the LSI, the central control unit translates the terminating number from the subscriber of the low-speed terminal 7 and determines the outgoing route, that is, the 64 Kbps outgoing channel (step 5300). Each output channel is managed by a management table that records the number of low-speed channels included therein and the usage status, and the number of low-speed channels used is determined (step 5301). As a result of the judgment,
If the number of low-speed channels in use is -0, an empty low-speed channel is hunted (step 5302), and the state of the low-speed channel is set to the busy state. The number of low-speed channels used is incremented by 1 (step 3303). A low-speed channel display indicating that a low-speed channel is multiplexed in the calling signal for making a call to TS2, and a channel unset display indicating that the low-speed channel among the outgoing channels will be used first. Add and edit step 5304), C
5NW3 (step 5305) and activates TS2.

In step 5301, if the number of low-speed channels in use≠0, it is determined whether all the low-speed channels (8 channels in this case) included in the outgoing channels are in use, and if they are in use (=8), they are considered busy. (Step 5306). If the number of used channels≠8, an unused low-speed channel is hunted (step 5307), and the number of used channels is increased by 1 (step S308). Here, the LSI edits the signal for connecting to TS2, but unlike the process in step 5304, it edits by adding a channel setting display indicating that the low-speed channel among the output channels is already in use (
Step 5309).

Depending on the information added to this calling signal, TS2 performs the following switching operations.If there is a low-speed channel indication, TS2
2 executes call processing for low-speed channel connection, and if this display is not present, normal processing is performed. Call processing for low-speed channel connection first determines the low-speed channel setting display, and if this display is not set, performs number translation based on the called number included in the activation signal, determines the route, and sets the call path. do. Further, if the low-speed channel setting display is set, the route and communication path have already been set in TS2, so the setting of the communication path is not performed. The number of low-speed channels used among communication channels is managed within TS2, and when releasing a channel by disconnecting a call, this number is checked and the communication path is only disconnected when this number reaches ``0''. do.

〔Effect of the invention〕

As explained above, the present invention adds a multiplexing indication bit to the connection signal indicating that calls from low-speed terminals on the same route are multiplexed at the subscriber time-division exchange on the calling side. This has the effect of realizing a time-division switching system that efficiently communicates low-speed calls without changing the switching speed of the relay time-division switching equipment, that is, without increasing the amount of memory.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a time division switching system showing an embodiment of the subrate communication method of the present invention, FIG. 2 is a diagram showing an example of a pattern in which a low-speed channel is multiplexed on the speech channel in FIG. 1, and FIG. FIG. 2 is a flow diagram showing a call processing flow of a low-speed call in the subscriber time-division exchange in FIG. 1; 1...Subscriber time division switch (LS), 2...Transit time division switch (TS), 3...Common signal network (CSNW)
), 4.5... Relay transmission line, 6... Telephone terminal, 7.
...Low speed terminal, 11...Telephone line time switch (T
Dt), 12...Low speed line time switch (TD
D), 13...Multiple conversion device (MUX). Island N, - Te 1 Artwork 2 Illustration KbpS

Claims (1)

[Claims] In a time-division switching system comprising a subscriber time-division exchange, a relay time-division exchange, and a signal network for transmitting and receiving connection signals between these two exchanges, the subscriber time-division exchange is a low-speed switch that accommodates low-speed terminals. a time switch; and a multiplex conversion device that multiplexes calls on the same route among calls exchanged by the low-speed time switch and sends the same route to the relay time division switch, and when the multiplex conversion device multiplexes the calls. A subrate communication system characterized in that a low-speed multiple display bit is added to the connection signal and transmitted to the signal network.