JPS6363144B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a multiparty communication system using digital subscriber lines.

Conventional multiparty calling services are typically provided by superimposing predetermined multiparty voices on a dedicated trunk inside a telephone exchange.

Therefore, due to the electrical characteristics of the trunks involved in multiparty calls, the number of multiparty calls has to be limited to a relatively small number.

Further, in order to provide this service, telephone exchanges must be equipped with a wide variety of trunks, and the exchange connection process is extremely complicated.

SUMMARY OF THE INVENTION An object of the present invention is to provide a multi-party call system which eliminates the above-mentioned drawbacks of the prior art, simplifies exchange connection processing, and facilitates a large number of multi-party calls.

A feature of the present invention is that the digital subscriber telephone is provided between a subscriber telephone and a digital subscriber line, and superimposes audio signals from a plurality of other subscriber telephones received from the digital subscriber line and sends the same to the subscriber telephone. sending out,
Furthermore, there is a multi-party communication device in which a voice signal from the subscriber's telephone is further superimposed on the voice signal and can be sent to each of the other subscriber's telephones through a digital subscriber line.

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a block diagram of an embodiment of a multi-party communication device according to the present invention.

Here, 1 is a subscriber telephone, 2 is a transmitting side digital subscriber line, 3 is a receiving side digital subscriber line, 4 is a multiparty communication device, 41 is its signal circuit, 42 is, 43 is the same multiplexer, 44A, 44B, 44C are the same demultiplexer,
Same analog/digital converter, 45A, 45
B, 45C is the same digital-to-analog converter,
46A, 46B, 46C are the same subtracters, 47, 4
8 is the same first and second superimposing device, and 49 is the same hybrid circuit.

This embodiment includes a subscriber telephone 1 and, for example,
Although it is possible to make up to four-party calls with three other subscriber telephones A, B, and C, analog/digital converters 44A, 44B, 44C, digital/analog converters 45A, 45B, 45C, and By adding necessary items in addition to the subtracters 46A, 46B, 46C, etc., the digital subscriber line 2,
It is possible to make multiparty calls with up to the same number of other subscriber telephones as the number of multiple channels of 3.

This can be easily achieved, for example, by using a broadcast communication function.

That is, a plurality of outgoing and incoming calls can be simultaneously connected to the subscriber telephone 1 according to the number of multiple channels of the digital subscriber lines 2 and 3.

Voice signals and control signals from subscriber telephones A, B, and C are digitally multiplexed and arrive at multiparty communication device 4 through digital subscriber line 3.

These are demultiplexed for each receiving channel in a demultiplexer 43, and converted into analog voice signals by digital-to-analog converters 45A, 45B, and 45C corresponding to subscriber telephones A, B, and C, respectively. be done.

In this case, the digital-to-analog converter 45
Additional codes A, B, and C of A, 45B, and 45C correspond to subscriber telephones A, B, and C, respectively, and the same applies to blocks with other additional codes hereinafter.

In this way, the digital voice signals from subscriber telephones A, B, and C are converted into analogs, mixed in the superimposer 47, and sent through the hybrid circuit 49 to the subscriber telephone 1, where they are listened to by the subscriber. be done.

On the other hand, control signals for each subscriber telephone A, B, and C are demultiplexed by a demultiplexer 43 and then input to a signal circuit 41, from which a calling signal and other necessary signals are sent to the subscriber telephone 11. be done.

Further, the signal circuit 41 detects off-hook, on-hook, dial, etc. signals of the subscriber telephone 1, and inserts necessary control signals in analog-to-digital converters 44A, 44B, and 44C corresponding to each channel. urge

The analog voice signal from the subscriber telephones passes through a hybrid circuit 49 and is mixed with the output of the superimposer 47 (a mixture of the voice signals from subscriber telephones A, B, and C) in a superimposer 48.

This output is sent to the digital-to-analog converter 4 by subtracters 46A, 46B, and 46C, respectively.
Audio signals for subscriber telephones A, B, and C are created by subtracting the outputs of 5A, 45B, and 45C at a predetermined rate.
It is input to B and 44C.

Although this is not necessarily necessary, this is done in order to appropriately suppress the own audio signals for subscriber telephones A, B, and C, and to provide good audio signals without producing more sidetone than necessary. belongs to.

In this manner, the voice signals for each subscriber telephone set A, B, and C are digitized by analog-to-digital converters 44A, 44B, and 44C, digitally multiplexed by multiplexer 42, and placed on the corresponding transmission channel. and each subscriber telephone A, B, C through the digital subscriber line 2.
transmitted to.

As a result of the above, the restriction on the number of multiparty calls as in the conventional example is relaxed, and high quality multiparty calls between subscriber telephone 1 and A, B, and C can be performed without deterioration of call quality due to multiple connections. be exposed.

In the above embodiment, in the case of a received audio signal,
Although this is done in an analog manner by the superimposer 47, the outputs of the demultiplexer 43 may be mixed digitally.

In this case, the digital-to-analog converter of the received audio signal need not be performed for each channel, but may be performed for the mixed signal all at once.

Furthermore, regardless of whether the received audio signals are mixed analogously or digitally, the subtraction of the audio signals from each subscriber telephone A, B, and C is performed digitally before the multiplexer 42. Good too.

As described in detail above, according to the present invention, the exchange side can simplify the exchange connection processing by, for example, using the broadcast communication function, and can also make high-quality multi-party calls. Therefore, a remarkable effect can be obtained in making the service function of the telephone exchange more economical and improving the quality of subscriber service.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of a multi-party communication device according to the present invention. 1... Subscriber telephone, 2, 3... Digital subscriber line, 4... Multi-party communication device, 41... Signal circuit, 42... Multiplexer, 43... Demultiplexer, 44A, 44B, 44C... Analog・Digital converter, 45A, 45B, 45C
...Digital to analog converter, 47, 48...
...Superimposed device, 49...Hybrid circuit.

Claims (1)

[Claims] 1. In a multi-party call system in which a multi-party call is made between a plurality of subscriber terminals via a digital subscriber line,
A multiparty communication means is provided between each subscriber terminal and the digital subscriber line, and the multiparty communication means receives digital signals from other subscriber terminals arriving at the receiving channel of the digital subscriber line connected thereto. a means for demultiplexing the signals, a first superimposing means for mixing and outputting the demultiplexed signals, and a means for outputting the mixed output signal to a subscriber terminal connected to the multiparty communication means; The demultiplexing means and the first
or between the first superimposing means and the outputting means, and the output signal mixed by the first superimposing means is connected to the multi-party call. a second superimposing means for further mixing and outputting signals from subscriber terminals connected to the multiparty communication means; means for analog-to-digital conversion of output signals from the subscriber terminals connected to the multiparty communication means; means for subtracting digital signals from other subscriber terminals arriving at the receiving channel of the digital subscriber line at a predetermined rate for each transmission channel from the output signal mixed by the second superimposing means; and means for digitally multiplexing the output signals and sending them to each transmission channel of the digital subscriber line. 2. The multi-party calling system according to item 1, wherein the terminal is a telephone and the digital signal is a voice signal.