JPH02134945A - Packet switchboard - Google Patents

Abstract

PURPOSE:To use a packet switchboard economically and conveniently by providing a switching device which selects a facsimile signal digitizing device when detecting a called station discrimination signal and accommodating an audio medium and a facsimile medium in the same telephone line. CONSTITUTION:A telephone set 1 and a G3 facsimile terminal 2 are connected to a same telephone line 3; and when the telephone set 1 originates a call, switching devices 4 and 6 are connected to an audio encoding/decoding device 7, and a sent signal is encoded and is sent to a digital signal PAD device 9. When the G3 facsimile terminal 2 originates a call, they are first connected through the audio encoding/decoding device 7, and a CED detecting circuit 5 detects CED sent from a device on the terminating side thereafter to switch switching devices 4 and 6 to a facsimile signal digitizing device 8, and this communication is kept hereafter till release of the line. Thus, the audio medium and the facsimile medium can be accommodated, in the same telephone line 3, and this switchboard is used economically and conveniently.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a packet switching device, and more particularly to a packet switching device that provides services by connecting voice media and facsimile media to the same telephone line.

[Conventional technology]

Conventional packet switching equipment assumes that telephone lines are only used for voice media, and uses voice encoding/decoding equipment to compress voice bandwidth. When used, as in the case of voice, it goes through a voice encoding/decoding device and performs band compression, which causes distortion and prevents normal facsimile communication. For this reason, voice media and facsimile media have been serviced by accommodating them on separate lines.

[Problem to be solved by the invention]

The conventional packet switching device described above provides services by accommodating voice media and facsimile media on separate lines, so there is a problem in that twice as many lines are required, which is uneconomical.

An object of the present invention is to provide a packet switching device that is economical and convenient to use by making it possible to accommodate voice media and facsimile media on the same telephone line.

[Means to solve the problem]

The packet switching device of the present invention includes a called station identification signal detection circuit that communicates with voice media and facsimile media connected to the same telephone line, and detects a called station identification signal sent by the called side in facsimile communication; AD information
Switching to select a voice encoding/decoding device that performs encoding and decoding using the PCM method, and to select a facsimile signal digitizing device when the called station identification signal detection circuit detects the called station identification signal. The configuration includes a device.

〔Example〕

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

FIG. 1 is a block diagram of one embodiment of the present invention.

The telephone 1 and the G3 facsimile terminal 2 are connected to the same telephone line 3. The telephone line 3 includes a switching device 4 in the packet switching device and a called station identification signal detection circuit that has a function of detecting a called station identification signal (hereinafter referred to as CED) sent from a facsimile terminal, etc. on the receiving side. (hereinafter referred to as CED detection circuit) 5 is connected. Between the switching device 4 and the switching device 6, received information (usually audio information) is
A voice encoding/decoding device 7 having a function of encoding and decoding using the DPCM method and a facsimile signal digitizing device 8 that converts facsimile signals into digital signals are provided. The CED detection circuit 5 has a function of instructing switching of devices connected to the switching device 4 and the switching device 6 when detecting a CED. The switching device 6 is further connected to a digital signal PAD device 9 for connection to other packet switching devices or lines of other terminals. The digital signal PAD device 9 receives other digital signals PAD.
It is connected to the device 10 via a communication bus 11. Connected to the communication bus 11 is a call connection processing device 12 that controls the connection of packet signals via a plurality of digital signal PAD devices in this packet switching device. Although not shown in the figure, the digital signal PAD device 10 can accommodate terminals belonging to the same packet switching device, or can accommodate terminals belonging to the same packet switching device via a data line. It is also possible to establish a packet-switched connection by connecting to

Next, the operation will be explained.

When the telephone 1 makes a call, the switching devices 4 and 6 are normally connected to the voice encoding/decoding device 7, so the transmitted signal is encoded using the ADPCM method and converted into a digital signal P.
It is sent to the AD device 9. The subsequent connection operation is performed by a known method under the control of the call connection processing device 12. When a call is made from the G3 facsimile terminal 2, the connection is first made via the voice encoding/decoding device 7, similar to when the telephone 1 makes the call. After that, the CED sent by the receiving device
The CED detection circuit 5 detects the switching device 4 and the switching device 6.
Instructs to switch the currently connected device. As a result, the device to be connected is switched from the voice encoding/decoding device 7 to the facsimile signal digitizing device 8, which is then held until the line is restored.

The above explanation was for the case of an outgoing call, but the case of an incoming call is almost the same.The only difference is that the detecting CED is connected to the telephone line 3 to which it is connected. This means that the signal is from the G3 facsimile terminal 2 that is currently in use.

FIG. 2 is a block diagram of one embodiment of the CED detection circuit.

Input signal i is an analog signal being sent and received on a telephone line. The call connection state detection circuit 21 has a function of detecting that a call setting connection has been made.

The 2100 Hz signal detection circuit 22 is a detection circuit for CED, which is a 2100 Hz signal. The counter circuit 23 is
When the 2100 Hz signal detection circuit 22 detects CED, it measures its duration, and when it detects that it has continued for a certain period of time, sets the SR flip-flop 24. S
R flip-flop 2/] has a function of transmitting a CED detection signal j to the outside when set by the 21.00 Hz signal detection circuit 22.

〔Effect of the invention〕

As described above, the present invention has the advantage of being economical and convenient to use by making it possible to accommodate voice media and facsimile media on the same telephone line.

...2100Hz signal detection circuit, 23...
Counter circuit, 24...SR flip flip 17
Tub, ■...Input signal, J...CED detection signal.

Claims (1)

[Claims] A called station identification signal detection circuit communicates with voice media and facsimile media connected to the same telephone line and detects a called station identification signal sent by the called side in facsimile communication, and normally encodes and encodes received information using the ADPCM method. and a switching device that selects a voice encoding/decoding device that performs decoding and switches the connection to select a facsimile signal digitizing device when the called station identification signal detection circuit detects the called station identification signal. Characteristic packet switching equipment.