JPH01162454A - Sub-rate exchanging system - Google Patents

Abstract

PURPOSE:To avoid the unnecessary increase of a multiplexing trunk and to decrease a cost by using and exchanging a multiplexing trunk only when plural sub-rate calls occur. CONSTITUTION:At a line circuit LC, an incoming line divides the output of an interface IF to two directions, introduces it to an exchanging network NW and introduces the signal of two time slots through an AND gate and AND to the interface IF even concerning an outgoing line. For example, the data of b0, b1-bn are separated and outputted in two directions at the incoming line. On the other hand, at the outgoing line, when the first bit of the data inputted is 1, it enters a line L1 directly through a network NW. When a sub- rate call after the second one occurs (when data are b0, 1, 1,...) while a first sub-rate call exists, the sub-rate call after the second one exchanged and connected through a multiplexing trunk MXT to the network NW is inputted to a line L2.

Description

[Detailed Description of the Invention] [Summary] Regarding a line circuit subrate switching method when multiple subrate calls occur in a digital exchange capable of exchanging digital data calls, multiplexing is performed only when multiple subrate calls occur. The purpose is to provide a subrate switching system that minimizes the number of multiplexed trunks and reduces costs by using trunks, and has a terminal adapter and a function that separates signals sent and received from the line side into two time slots. The first time slot of the first subrate call is exchanged as it is in the switching network, and the first subrate call is present on the line. and a controller having a function of connecting the second time slot to the multiplexed trunk and connecting the second and subsequent subrate calls via the multiplexed trunk only when a second or subsequent subrate call occurs during the time period. , the multiplexed trunk is used for switching only when a plurality of subrate calls occur.

[Industrial Field of Application] The present invention relates to a subrate switching system for line circuits when a plurality of subrate calls occur in a digital exchange capable of switching digital data calls.

[Prior Art] Switches in conventional digital exchanges are exchanged, for example, in units of 8 bits at a cycle of 8KH2, resulting in 64 bits.
FIG. 3 is a block diagram showing an example of a digital exchange in which K bps exchange is performed. In the figure, TO is a terminal controller, which is a controller that controls terminals (telephones and data terminals). MX is a multiplexing circuit that multiplexes data from each terminal group exchanged into 8-bit parallel data by the serial/parallel exchange means SP.

The SPM is a channel memory that sequentially stores data from the multiplexing circuit MX in 8-bit units at each address, and stores each address in the order specified by the control memory CM (memory that stores the order of address switching). It performs switching and outputs its contents.

DMX is a separation circuit that separates the output of the channel memory SPM into sets corresponding to each terminal. The separated data (8-bit parallel data) is sent to parallel and serial means PS, respectively.
is converted to serial data via

Note that the downlink is connected so that data is directly transmitted to the terminal without passing through the channel memory SPM.

[Problems to be Solved by the Invention] On the other hand, as shown in FIG. 4, eight 8-bit data terminals (To-T7
) of data and connects each data signal to different parties, the following methods were available.

■As shown in Figures 5 and 6, a system in which the switch exchange unit is 8 Kbps.

However, in this method, the exchange unit is 1 bit, so in order to exchange a normal audio signal (64'Kbps), 8 bits are required.
There is a problem that time slots 1 to 1 are required, and the number of accommodated terminals decreases.

■As shown in Figure 7, a method in which the line circuit transfers the data to a 64 Kbps time slot every 8Kbps.

In the figure, 5R-LC is a subscriber line circuit, which is composed of an interface IF and a multiplexing/demultiplexing circuit MX/DMX that performs multiplexing and demultiplexing.

Although the multiplexing/demultiplexing circuit is shown with uplink and downlink circuits grouped together, in reality, the hybrid circuit 1''BC is composed of a cog and a decoder.

Also, the voice signal output from the telephone (uplink) is encoded into an 8-bit signal by the uplink KOG CD via the hybrid circuit 1-IBG, and is input to the switching network MW (uplink). On the other hand, in the downlink, 8-bit data from the switching network is decoded by the decoder DCD and sent to the telephone via the hybrid circuit HBC.

Note that solid lines illustrated in the switching network NW indicate connections between data terminals.

However, in such a system, the subscriber line circuit 5R-L
The problem is that C becomes complicated.

■As shown in Fig. 8, a system in which mixer trunk MX kings that multiplex and demultiplex subrate data calls are hand-connected when a data call occurs.

That is, data from the terminal adapter TA is input via the line circuit LC to the mixer trunk MXT connected to the back of the switching network NW.

This mixer trunk MXT is a multiplexing/separating circuit MX/
It is composed of DMX, and input data from the incoming line is multiplexed and sent to the switching network NW, while data output from the switching network is then separated and output to the outgoing terminal.

However, although there are actually very few calls in which subrate calls are multiplexed on the same channel, multiplexed trunks must be connected every time a data call occurs, requiring a large number of mixer trunks and increasing costs. There is a problem with rising.

In view of these points, the present invention takes into consideration that there are few cases where multiple subrate calls exist on the same channel, and uses multiplexed trunks only when multiple subrate calls occur. The objective is to provide a subrate exchange system that can minimize the number of subrate exchanges and reduce costs.

[Means for solving the problem] FIG. 1 is a block diagram of the principle of the present invention. In the figure, TA is a terminal adapter, which is a data terminal that can send and receive digital data (for example, To, T1 to T8, T9, etc.)
multiplexes or separates the signals. The MXT is a multiplexing trunk that multiplexes incoming data on the upstream line and separates data from the switched network on the downstream line.

NW is a switching network. The LC is a line circuit that has the function of sending data from a data terminal to the switching network NW and inputting data from the switching network NW to the data terminal. slot).

C0NT is a controller, and when the first subrate call occurs on the line, the first time slot of the line circuit LC is used to directly exchange it in the switching network, and when the first subrate call is present, If a second or later subrate call occurs during the time slot, the second time slot is connected to the multiplexed trunk MXT, and the second or later subrate call is connected via the multiplexed trunk MXT.

[Function] In the present invention, when the first subrate call occurs on the line, the controller C0NT uses the first time slot of the line circuit LG to directly connect the call to the switch on the exchange network NW for exchange. If a second or subsequent subrate call occurs while the first subrate call exists, the second time slot is multiplexed into the trunk M.
XT and connects the second and subsequent subrate calls via the multiplexed trunk MXT. As a result, the multiplex trunk MXT can be effectively connected only when necessary, instead of unconditionally connecting the multiplex trunk MXT every time a data call occurs. Therefore, inadvertently multiplexing trunk M
There is no need to increase the number of XTDs.

It should be noted that communication of telephone signals does not go through the multiplexed trunk MXT, but is performed by direct connection in the switching network NW as in the past.

[Example] Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 2 is a configuration diagram showing an embodiment of the present invention, and in the figure,
Components that are the same as those shown in FIG. 1 are designated by the same reference numerals. In the line circuit LC, ■F is an interface that controls data transmission and reception between the data terminal and the switching network NW.

Then, the up line connects the output of the interface IF to 2
For the down line, the signals of two time slots are also guided to the interface IF via an AND gate AND.

An example of communication data on each line shown in the figure will be explained. On the up line, bQ, bl, b2,・
..., bn data is separated into two directions and output.

On the other hand, when the first bit of input data is 1 on the down line, it is transmitted directly through the switching network to line L1.
comes into the. If a second or subsequent subrate call occurs while the first subrate call exists (if the data is bo, 1.1...), the multiplex trunk MXT
The second and subsequent subrate calls that are switched and connected to the switching network NW are input to line L2.

Although the present invention has been described above with reference to embodiments, the embodiments of the present invention are not limited to these embodiments, and the scale can be modified in accordance with the spirit of the present invention.

[Effects of the Invention] As explained above, according to the present invention, it is considered that there are few cases where multiple subrate calls exist on the same channel, and multiplexed trunks are used only when multiple subrate calls occur. Therefore, an unnecessary increase in the number of multiplexed trunks can be avoided and costs can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the principle of the present invention, FIG. 2 is a configuration diagram of an embodiment of the present invention, and FIGS. 3 to 8 are diagrams for explaining the conventional switching system. In Figure 1, T△ is a terminal adapter, LO is a line circuit, NW is a switching network, MXT is a multiplex trunk, and C0NT is a controller.

Claims (1)

[Claims] A digital exchange capable of exchanging digital data calls includes a terminal adapter (TA) that multiplexes or demultiplexes signals from a data terminal capable of transmitting and receiving digital data; A line circuit (LC) that has the function of separating into two time slots, a switching network (NW), and a multiplex trunk (MXT) that multiplexes input data on the upline and separates data from the switching network on the downline. ), and when a first subrate call occurs on the line, the first time slot of the line circuit (LC) is used to directly perform switching in the switching network (NW),
If a second or subsequent subrate call occurs while the first subrate call exists, the second time slot is connected to the multiplex trunk (MXT) and the second or subsequent subrate call is transferred to the multiplex trunk. (MXT) and a controller (CONT) that has a function to connect via (MXT), and only when multiple subrate calls occur, the multiplexed trunk (
A subrate exchange method characterized by using MXT) for exchange.