JP2518322B2 - Digital subscriber line carrier system - Google Patents

Description

The present invention relates to a digital subscriber having a function of multiplexing various subscriber line signals such as a plurality of subscriber telephones and ISDN subscriber lines into a PCM primary group signal. It relates to a line transfer system.

[Prior Art] Conventionally, a digital subscriber line carrier system of this type is multiplexed by distributing pulses for positioning from a common control unit to each channel and taking a wired OR of each output. It was a method to do.

[Problems to be Solved by the Invention] The conventional digital subscriber line carrier system described above has the following drawbacks. For example, when converting the voice signal of a conventional analog telephone into a digital carrier, one time slot is occupied because 64 kb / s is used on the PCM primary group signal,
The ISDM telephone signal uses 192 kb / s on the PCM primary group signal and therefore occupies 3 time slots. Therefore, one digital subscriber line carrier is used for analog telephone subscribers and ISDM.
When accommodating both telephone subscribers, a channel board occupying one time slot and a channel board occupying three time slots are mixed. When a channel board having three time slots exclusively used for ISDN subscriber lines and a channel board having two sets of analog subscriber telephone circuits having one time slot exclusively installed are mixed in the same device, To prevent the slots from overlapping, it is necessary to allocate 3 time slots from 4 time slots for 2 sets of analog subscriber telephone circuits, and 4 time slots must be allocated to the ISDN subscriber line in advance. Time slots are wasted.

This is because if there are not enough subscribers to fill the time slots on the PCM primary group signal, there is no problem in using them with some time slots open, but since one subscriber cannot be accommodated, digital In some cases, it is necessary to add another subscriber line carrier, and in order to construct a cost-minimized system, it is necessary to waste time slots as little as possible.

[Means for Solving Problems] In the digital subscriber line carrier system of the present invention, a reference pulse signal commonly given to each channel board and an address signal determined by a position where the channel board is mounted are input. , A channel pulse generation circuit for outputting a signal indicating a time slot to be occupied by its own channel, and n time slots (n = 1, n = 1,
, ...) and a wired OR circuit that determines whether to output the n time slots as they are or to put them in a high impedance state by a control signal from the outside. The control signal is time-synchronized with the time slot on the PCM primary group signal, and when the corresponding time slot is output, only that time slot has a logical value "1" and is not output and is in a high impedance state. When it is set to "0" and all the time slots for which the output of the channel board is not output are logical values "0".

[Operation] According to the configuration of the present invention, a channel board on which two channels of subscriber circuits exclusively for one time slot are mounted,
A subscriber who occupies 1 time slot in the next time slot of the channel board output that occupies 3 time slots even when a channel board that occupies 3 time slots for 1 subscriber line input coexists. Circuit is 2
Time slots can be continuously used by directly outputting one channel of the channel board on which the channels are mounted by the control signal and setting the remaining one channel in a high impedance state by the control signal.

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

FIG. 1 is a block diagram showing an embodiment of the present invention.
FIG. 2 is a time chart explaining the operation of the embodiment shown in FIG.

The channel board according to the present invention inputs a reference pulse signal commonly given to each channel board and an address signal determined by a position where the channel board is mounted, and outputs a signal indicating a time slot to be occupied by its own channel. Channel pulse generator circuit 1, a subscriber line interface circuit 2 that outputs the received subscriber line signal to the signal position indicating the time slot for n time slots after digitizing the received subscriber line signal, and the n time slot portions as they are. Wired that is determined by an external control signal whether to output or set to high impedance state
It is composed of an OR circuit 3.

The channel pulse generation circuit 1 compares the reference pulse as shown in FIG. 2 (a) with the address input determined by the mounting position of the channel board, and outputs the signal 11 indicating the time slot position to be output by the own channel. To do. The subscriber line interface circuit 2 digitizes the subscriber line input at the time slot position indicated by the signal 11 indicating the time slot position for n time slots) n = 1, 2, ... . The wired OR circuit 3 outputs the output of the subscriber line interface circuit 2 as it is according to the output control signal or puts it in a high impedance state. The output control signal is time-synchronized with the time slot on the PCM primary group signal, and when the corresponding time slot is output, only the time slot is set to the logical value "1" and is not output and is in a high impedance state. In that case, the logical value of that time slot is “0”.

When only a channel board including two sets of the above circuits with n = 1 is mounted in the same device (referred to as A channel and B channel, respectively), the output of the wired OR circuit 3 is as shown in FIG. 2 (b). (1, 2, 3, ... Indicates the numbers on the channel board).

That is, the output of the channel board that accommodates two circuits for carrying analog telephone signals is two time slots (A
Channel and B channel), so 24
A 1.544 Mb / s PCM primary group signal with a time slot (upper limit value) can use all time slots on 12 channel boards.

However, there is only one channel board for ISDN telephone signals.
If 11 channels of analog telephone signal channel boards are installed, the ISND telephone signal channel board occupies 3 time slots, so a total of 25 time slots are required, and all signals must be carried. Will not be possible. This is because the third time slot of the three time slots of the ISDN channel board collides with the A channel of the two time slots of the analog telephone channel board mounted on the right side of the ISDN channel board ( However, the time slots shall be assigned from left to right according to the mounting position of the channel board).

Therefore, it is necessary to make the A channel unused by some method. Therefore, in the case where a channel board in which one subscriber line input such as n = 3 exclusively uses three time slots and a channel board including two sets of the above-mentioned n = 1 subscriber circuit are mounted in the same device. In the first step, the wired OR circuit 3 of the channel A of the channel board mounted on the right side of the channel board that exclusively occupies 3 time slots is set to the high impedance state by the output control signal. As a result, the multiplexed output of the wired OR circuit 3 becomes as shown in FIG. 2 (c), and the time slot can be multiplexed without wasting it.

[Effects of the Invention] As described above, the present invention determines the time slot to be occupied by the own channel by comparing the reference pulse signal with the address signal determined by the mounting position of the channel board, and digitizes the position at that position as necessary. A channel in which two sets of subscriber circuits having one time slot are mounted on the same channel board by transmitting the subscriber line input signal and outputting the transmission signal from the wired OR circuit controlled by the output control signal. Even if a board and a channel board that occupies three time slots or more for one subscriber line are mixed in the same device, one time slot can be multiplexed without being wasted.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a time chart for explaining the operation of the embodiment of FIG. 1 ... Channel pulse generation circuit, 2 ... Subscriber line interface circuit, 3 ... Wired OR circuit.

Claims (1)

(57) [Claims] 1. A plurality of subscriber telephones and ISDN subscriber line signals are transmitted to a PC.
In a digital subscriber line carrier having a function of multiplexing with an M primary group signal, a reference pulse signal commonly given to each channel board and an address signal determined by the position where the channel board is mounted are input, A channel pulse generating circuit for outputting a signal indicating a time slot to be occupied by a channel, and n time slots (n = 1, 2, ...) The subscriber line interface circuit to be output and the wired that is determined by an external control signal whether to output the n time slots as they are or to put them in a high impedance state.
And an OR circuit, the control signal is time-synchronized with a time slot on the PCM primary group signal, and when the corresponding time slot is output, only that time slot is output with a logical value "1". A digital subscriber line carrier system in which the signal is a logical value of "0" for all timeslots that are not subject to output on the channel board and are not put into the high impedance state.