JPH0771318B2 - Digital interface device - Google Patents

Description

The present invention relates to a digital interface device in a digital exchange.

[Conventional technology]

Conventionally, this type of digital interface device does not have a function of controlling a code conversion device that band-compresses a PCM signal in accordance with a predetermined rule, and has a configuration combined with this code conversion device.

[Problems to be solved by the invention]

Since the above-described conventional digital interface device is configured to be combined with the code conversion device, deterioration of sound quality increases each time relay exchange is repeated. In order to prevent deterioration of sound quality, it is necessary to divide into a relay-dedicated route without a transcoding device and an extension connection-dedicated route with a transcoding device.

[Means for Solving Problems] A digital interface device of the present invention is connected to a code conversion device for band-compressing a PCM signal according to a predetermined rule and a time division switch of an exchange, and performs code conversion in the code conversion device. First means for generating a bit string for controlling activation and stop of a function, and second means for multiplexing the bit string with a PCM signal to be sent to the code conversion device.
And means for transmitting from the central control circuit of the exchange based on whether the signal of the digital line input to the code conversion device is for relay switching or extension connection. The configuration is controlled by an instruction.

〔Example〕

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

Referring to FIG. 1, FIG. 2 and FIG. 3 showing an embodiment of the present invention, in this embodiment, as shown in FIG.
O) for the frame sync signal and time slot 16 (TS1
6) is assigned to control the code converter. Since one time slot consists of 8 bits, a 4-multiframe structure is adopted to fill a trunk circuit for 30 channels, and one control bit is given to each time slot.

In response to an instruction from the central control circuit 37 of the exchange 33, the peripheral control circuit 12 of the digital interface circuits 34 and 36 writes the code converter control data in the flip props (Q _{0 to} Q ₃₁ ) 13 corresponding to the time slot numbers. The written data is bit-multiplexed by the bit string creating / multiplexing circuit 14 into the 4-multiframe structure shown in FIG.
The PCM signal string 11 and the control bit string are multiplexed. The control counter 16 controls the multiplexing circuits 14 and 15 so that the multiplexed signal has the frame structure shown in FIG. The signal train multiplexed by the multiplexer 15 is converted into a bipolar signal by the signal converter 17 and sent out to the code converter.

In FIG. 3, when the signal from the incoming digital line is relay switching, the central control circuit 37 is relay switching to the peripheral control circuit 12 of the incoming digital interface circuit 34 and the outgoing digital interface circuit 36. Communicate information to the effect. When the peripheral control circuit 12 of the digital interface circuits 34 and 36 writes the code conversion stop information in the corresponding time slot position of the flip-flop, the information is
It is sent to the code conversion devices 31 and 32 together with the PCM signal sequence, and the code conversion function of the corresponding time slot is stopped to make the signal path transparent. The signal from the incoming digital line passes through the call path a and the time division switch 35 in the exchange 33,
It is sent to the output side digital circuit through the output side digital interface circuit 36 and the output side code converter 32 in the same signal format as when it arrived. On the other hand, if the signal from the incoming digital line is connected to the extension telephone 38, the central control circuit
37 informs the peripheral control circuit 12 of the input side digital interface circuit 34 that it is an extension connection. Peripheral control circuit
Reference numeral 12 writes the code conversion start information in the corresponding time slot position of the flip-flop 13 and activates the code conversion device 31. The signal from the input side digital circuit is returned to the PCM signal string by the code conversion device 31 and reaches the extension telephone 38 through the communication path b and the time division switch 35. Conversely, extension telephone 38
The code conversion device 31 performs code conversion on the PCM signal and outputs the PCM signal to the digital line. Even if the multiplexing method and the number of control bits per channel are different, the same operation can be performed.

〔The invention's effect〕

As described above, according to the present invention, the trunk for relay and extension can be shared by controlling the start and stop of the code conversion function in the code conversion device.

[Brief description of drawings]

FIG. 1, FIG. 2 and FIG. 3 are views showing an embodiment of the present invention. 14,15 ... Multiplexing circuit, 16 ... Control counter, 17 ... Signal conversion circuit, 31,32 ... Code conversion device, 33 ... Converter, 3
4 …… Incoming side digital interface circuit, 35 …… Time division switch, 36 …… Outside digital interface circuit, 37 …… Central control circuit, 38 …… Extension telephone.

Claims (1)

[Claims] 1. A bit conversion unit for band-compressing a PCM signal in accordance with a predetermined law and a time division switch of an exchange to generate a bit string for controlling start and stop of a code conversion function in the code conversion unit. And a PC for sending the bit string to the code conversion device.
Second means for multiplexing into the M signal, wherein the first and second means are based on whether the signal of the digital line input to the code conversion device is for relay switching or extension connection. A digital interface device controlled by an instruction from a central control circuit of the exchange.