JPS6321381B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a voice switching system in which a plurality of voice terminal devices are connected through a common transmission path and a conference call can be made between any voice terminal devices. It is related to.

[Prior art]

Conventionally, the first voice exchange system of this type was
The one shown in the figure is known. FIG. 1 is a schematic configuration diagram showing an example of a conventional voice exchange system.
In Figure 1, 1a, 1b, 1c, 1d, 1e
1 is a transmission path, 2 such as 2a, 2b, 2c is a telephone communication device, 3 is a voice terminal device such as a telephone, and 4 is a management device.

Figure 2 shows the voice exchange system in Figure 1.
FIG. 2 is a configuration diagram of a frame used to transmit an audio signal. In Figure 2, 5 is a frame;
SYN is the synchronization pattern, CH1, CHi, CHj,
CHs such as CHk and CHn are communication channels. Frame 5 circulates through transmission line 1 shown in FIG. 1 at a cycle of 125 microseconds, and one communication channel CH within frame 5 is composed of 8 bits. Furthermore, a control signal for transmitting a signal (hereinafter referred to as a control signal) used for control such as a call origination/recovery request or channel allocation between the voice terminal device 3 and the management device 4 shown in FIG. Communication channel CH1 is assigned as the channel. Generally, in the voice exchange system described above, voice signals are encoded and decoded and transmitted as PCM (Pulse Code Modulation) codes as described below.

FIG. 3 is a circuit diagram of a PCM audio signal code/decoder applied to the audio exchange system of FIG. 1. In FIG. 3, 10 is a code/decoder unit;
1 is a sampling circuit, 12 is a compressor, 13 is an encoding circuit, 14 is a decoding circuit, 15 is an expander, 16 is an interpolation filter, and 50 and 51 are signal lines.

Next, the operation of the conventional voice exchange system described above will be explained. First, the operation of the circuit diagram of the PCM audio signal code/decoder 10 shown in FIG. 3 will be described. The audio signal output from the audio terminal device 3 via the signal line 50 is sampled at 8KHz every 125 microseconds by the sampling circuit 11.
The signal is converted to a PAM (Pulse AmPlitude Modulation) signal, and further passed through a compressor 12 and quantized.
PAM signal, and finally encoder circuit 13
It becomes a PCM code. The audio signal that has become a PCM code in this way (one PCM code is 8 bits) is transmitted at a transmission speed of 64 Kbps on one communication channel CH on transmission path 1 shown in Figure 1. . PCM imported from the above communication channel CH
The encoded audio signal is converted into a quantized PAM signal by a decoding circuit 14, and then passed through an expander 15 to become a PAM signal. This PAM signal is restored to the original audio signal through the interpolation filter 16 and output to the audio end device 3 via the signal line 51.

Now, the manner of voice exchange in the conventional voice exchange system shown in FIG. 1 will be described in detail below.

FIG. 4 is an explanatory diagram showing a voice exchange method in a conventional normal call (one-to-one call) in the first voice exchange system. In FIG. 4, for convenience of explanation, a voice terminal device 3a and a voice terminal device 3b are shown.
Furthermore, for this call, each of the communication devices 2a and 2b is connected to the communication channel CHi by sending and receiving control signals using the communication channel CH1 by the management device 4. It is assumed that communication channel CHj is assigned.
Note that A and B shown in FIG. 4 represent each voice terminal device 3a.
and 3b are output audio signals, and 6 is a time division switch.

When the communication channel CHi assigned to its own station is input through the transmission path 1a, the communication device 2a takes in the contents of this communication channel CHi, that is, the signal of the voice terminal device 3b, and sends it to the code/decoder shown in FIG. 10, the signal is restored to the original audio signal B and output to the audio terminal device 3a. Furthermore, the audio signal A from the audio terminal device 3a is converted into a PCM signal by the encoder/decoder 10, and is transmitted to the transmission path 1b on the communication channel CHi.

Similarly, the communication device 2b takes in the signal of the voice terminal device 3a through the communication channel CHj assigned to itself, restores it to the original voice signal A, and outputs it to the voice terminal device 3b. Further, the audio signal B output from the audio terminal device 3b is encoded into the encoder/decoder 1.
0 to PCM signal and communication channel CHj
and sends it out to the transmission line 1c.

In the management device 4, when the communication channel CHi and the communication channel CHj arrive from the transmission path 1e,
A time division switch 6 in the management device 4 exchanges signals in communication channels CHi and communication channels CHj. In other words, audio signal A that was on communication channel CHi is transferred to communication channel CHj, and audio signal B that was on communication channel CHi is transferred to communication channel CHi.
is transferred to the communication channel CHi and sent to the transmission path 1a. By repeating the operations described in (1) to (4) above, a call is made between each voice terminal device 3a and 3b.

Moreover, a plurality of speakers (three or more) talk to each other. In the case of a so-called conference call, it was done as described below. FIG. 5 is an explanatory diagram showing a conventional voice exchange method during a conference call in the voice exchange system of FIG. 1. In the example shown in FIG. 5, it is assumed that a conference call is being made between the respective audio terminal devices 3a, 3b, and 3c. In addition, in order to conduct a conference call, each communication device 2a,
2b and 2c are the management device 4 and the communication channel CH1
It is assumed that communication channels CHi, CHj, and CHk are assigned to each communication channel by exchanging control signals using . Reference numeral 7 in FIG. 5 denotes a trunk for conference calls, which is located in the management device 4, and performs the function of adding up the voices of all the callers excluding each speaker himself from all the callers making a conference call every frame 5. . Further, C in FIG. 5 is an audio signal output by the audio terminal device 3c.

When the communication channel CHi arrives from the transmission path 1a, the communication device 2a takes in the contents of this communication channel CHi, that is, the PCM signal obtained by adding the audio signals B and c of the audio terminal devices 3b and 3c, and transmits the audio terminal device 3a instead. PCM the audio signal A of
It is converted into a signal and sent to the transmission path 1b on the communication channel CHi. In addition, the telephone device 2a
is taken from the above communication channel CHi
The code/decoder 10 shown in FIG.
Convert it to the original audio signal and send it to the audio terminal device 3a.
The audio signal B+C is output to.

When the communication channel CHj arrives from the transmission path 1b, the communication device 2b takes in the contents of this communication channel CHj, that is, the audio signals A and C of the audio terminal devices 3a and 3c, and transmits the audio terminal device 3 instead.
The audio signal B of b is converted into a PCM signal and sent to the transmission path 1c on the communication channel CHj. Further, the communication device 2b is connected to the communication channel.
The PCM signal taken in from CHj is converted into the original audio signal by the code/decoder 10 shown in FIG. 3, and the audio signal A+C is output to the audio terminal device 3b.

When the communication channel CHk arrives from the transmission path 1c, the communication device 2c uses this communication channel CHk.
, that is, the PCM signal obtained by adding the audio signals A and B of the audio terminal devices 3a and 3b,
Instead, the audio signal C of the audio terminal device 3c is
Convert to PCM signal and use the above communication channel CHk
and sends it out to the transmission line 1d. Further, the telephone device 2c converts the PCM signal taken in from the communication channel CHk into the original audio signal using the code/decoder 10 shown in FIG. 3, and outputs the audio signal A+B to the audio terminal device 3c.

When the communication channels CHi, CHj, CHk arrive from the transmission line 1e, the management device 4 sequentially sends them to the conference call trunk 7. In the conference call trunk 7, the PCM-converted audio signals A, B, and C in the communication channels CHi, CHj, and CHk are accumulated every frame 5, and these signals are added to form the summed signals B+C, A+C,
A+B is generated and sent to the time division switch 6. The time division switch 6 sends an addition signal B+C to the communication channel CHi and an addition signal A+ to the communication channel CHj.
C is sent to the transmission path 1a with the addition signal A+B placed on the communication channel CHk. By repeating the operations described in ~ above, a conference call is performed between the audio terminal devices 3a, 3b, and 3c.

Since the conventional voice exchange system is configured as described above, each voice terminal device 3a, 3b, 3c
When a conference call is held between two parties, voices are intensively exchanged in the management device 4, so when making a conference call with several groups, there is a drawback that conference call trunks 7 corresponding to the number of groups are required. Ta. Further, the operation of the management device 4 is different between normal calls and conference calls, and there is a drawback that the device configuration for processing the calls is complicated.

[Summary of the invention]

The present invention has been made in order to eliminate the drawbacks of the conventional ones as described above, and includes a management device that includes a means for allocating a communication channel for a communication device to communicate with an arbitrary communication device via a transmission path, and means for notifying the communication device of the allocated communication channel; , means for selecting a communication channel assigned to the own telephone device and a communication channel assigned to the other party, and means for selecting a communication channel assigned to the own telephone device and a communication channel assigned to the other party, and a means for selecting an audio signal in the communication channel assigned to the other party, and an audio signal to be transmitted by the own telephone device. means for adding the audio signal to the communication channel and sending the resultant signal to the communication channel; ), and has a configuration that allows conference calls to be made between the communication devices, which facilitates the expandability of the entire system, and allows communication between normal calls and conference calls. It is an object of the present invention to provide a voice exchange system in which calls can be processed under the same control.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. FIG. 6 is an explanatory diagram showing a voice exchange method during a conference call in a voice exchange system that is an embodiment of the present invention. The example shown in FIG. 6 shows a case where a call is being made between each voice terminal device 3a, 3b, 3c. communication channel
It is assumed that CH1 is used to send and receive control signals, and each communication channel CHi, CHj, CHk used for voice exchange has been designated. In addition, the communication device 2
Communication channel CHi is used as the communication channel CH for reception of communication device 2b, and communication channel CHj is used for communication device 2b.
However, it is assumed that a communication channel CHk is assigned to each communication device 2c.

When the communication channel CHi arrives from the transmission path 1a, the communication device 2a takes in the content of this communication channel CHi, that is, the sum signal B+C obtained by adding the audio signal B of the audio terminal device 3b and the audio signal C of the audio terminal device 3c, The PCM signal is restored to the original audio signal and output to the audio terminal device 3a. Therefore, the audio terminal device 3a can listen to the audio signals B and C from the audio terminal devices 3b and 3c. The communication channel CHi carries a silent signal Y (for example, an analog zero-level silent PCM code "01111111") and sends it to the transmission path 1b. Further, the communication device 2a is connected to each communication channel.
When CHj and CHk arrive from the transmission path 1a, the contents of each communication channel CHj and CHk are added to the audio signal A of the audio terminal device 3a, and the signals A+C and A+Y (Y is a silent signal, so Specifically, only the audio signal A (hereinafter simply referred to as A) is transmitted to the transmission path 1b on the communication channel CHj and the communication channel CHk, respectively.

When the communication channel CHj arrives from the transmission path 1b, the communication device 2b takes in the content of this communication channel CHj, that is, the sum signal A+C obtained by adding the audio signal A of the audio terminal device 3a and the audio signal C of the audio terminal device 3c, The PCM signal is restored to the original audio signal and output to the audio terminal device 3b. Therefore, the audio terminal device 3b can listen to the audio signals A and C from the audio terminal devices 3a and 3c. A silent signal Y is carried on the communication channel CHj and sent to the transmission path 1c. Furthermore, when the communication channels CHi and CHk arrive from the transmission path 1b, the communication device 2b
The contents of CHi and CHk are added to the audio signal B of the audio terminal device 3b, and the signals B and A+B, which are made into PCM signals, are sent to the transmission path 1c on the communication channel CHi and the communication channel CHk, respectively.

When the communication channel CHk arrives from the transmission path 1c, the communication device 2c
The contents of CHk, that is, the sum signal A+B obtained by adding the audio signal A of the audio terminal device 3a and the audio signal B of the audio terminal device 3b, are taken in, restored from the PCM signal to the original audio signal, and output to the audio terminal device 3c. Therefore, the audio terminal device 3c can listen to the audio signals A and B from the audio terminal devices 3a and 3b. The above communication channel CHk includes
It carries the silent signal Y and sends it to the transmission path 1d. Further, the communication device 2c includes each communication channel CHi,
When CHj arrives from the transmission path 1c, the contents of each communication channel CHi, CHj and the audio signal C of the audio terminal device 3c are added, and the signal B is converted into a PCM signal.
+C and C are sent to the transmission path 1d on communication channels CHi and CHj, respectively.

In the management device 4, each of the communication channels CHi,
When CHj and CHk arrive from the transmission path 1e, they are synchronized with frames and sent out as they are to the transmission path 1a. By repeating the operations described in ~ above, a conference call can be made between the voice terminal devices 3a, 3b, and 3c without requiring the time division switch 6 or trunk 7 for conference communication shown in FIG. It will be done.

In addition, in the case of a normal call, for example, in FIG. 6, the voice terminal device 3a and the voice terminal device 3b
Assuming that a call is being made between the two, focusing on each communication channel CHi and communication channel CHj,
In the above explanations, the operation of the communication device 2c for these communication channels CHi, CHj,
Since it is the same as the one except for the communication channel CHk and the audio signal C, the explanation thereof will be omitted.

Next, the functions of each part constituting the communication device 2 applied to the voice exchange system of the present invention will be explained. FIG. 7 is a block diagram showing an embodiment of the telephone communication device in the voice exchange system of the present invention. In FIG. 7, 20 is a shift register for serial/parallel switching. 21 is a synchronization unit that detects a synchronization pattern SYN from frame 5 shown in FIG. Outputs channel identification signals for channel CH1 and other communication channels CH. Reference numeral 22 denotes a channel number memory that stores the numbers of the communication channel CH for reception and the communication channel CH of the other party. 23 is a comparison section, and a synchronization section 21
The communication channel CH for reception at the own station and the communication channel CH of the other party are selected by comparing the channel identification signal from the channel number memory 22 with the channel number stored in the channel number memory 22. 24 is a reception control unit that takes in the contents of the communication channel CH; 25 is an adder that adds the arriving voice signal in the communication channel CH to the voice signal from the voice terminal device 3 connected to the communication device 2; and 26 is a A silence signal generator 27 generates a silence signal (for example, an analog zero-level PCM code "01111111"), and a transmission control section 27 outputs a common line signal, an added voice signal, or a silence signal to the shift register 20. 28 is a common line signal control unit, using communication channel CH1,
It controls the exchange of control signals with the management device 4, such as call originating/incoming call requests and notification of allocation of communication channel CH for transmitting voice signals. Each of 100 to 107 is a signal line.

Next, taking the communication device 2a shown in FIG. 6 as an example, this communication device 2a is connected to each other communication device 2b,
Regarding the operation of each part above when talking with 2c,
This will be described below with reference to FIG.

(a) When the communication channel CHi for own station reception arrives When the comparison unit 23 is notified from the synchronization unit 21 via the signal line 100 that the communication channel CHi has arrived from the transmission path 1a, the comparison unit 23 The contents of the channel number memory 22 and the above notification are compared. In this case, since it is the communication channel CHi for own station reception,
The comparison section 23 includes a reception control section 24 and a transmission control section 27.
It is notified via the signal line 101 that the communication channel CHi for own station reception has arrived. Upon receiving this notification, the reception control section 24 receives the signal line 1 from the synchronization section 21.
02, the content of the communication channel CHi is fetched from the shift register 20 via the signal line 103 and output to the code/decoder 10. The code/decoder 10 converts the signal sent from the reception controller 24 into the original audio signal, and outputs the audio signal B+C to the audio terminal device 3. Similarly to the reception control unit 24, the transmission control unit 27 receives the arrival notification of the communication channel CHi from the comparison unit 23, receives the silence signal Y from the silence signal generator 26, and receives the silence signal Y from the synchronization unit 21 on the signal line 102.
according to the timing signal sent through the
The silent signal Y is sent to the shift register 20 via the signal line 104, and the contents of the communication channel CHi are changed to the silent signal Y. The shift register 20 converts the signal into a serial signal and sends it to the transmission line 1b.

(b) When the communication channel CHj or CHk of the other party arrives When the notification of the arrival of the communication channel CHj or CHk is received from the synchronization unit 21 to the comparison unit 23 as in the previous section (a),
The comparison unit 23 compares this notification with the channel number memory 22.
Compare the contents of As a result, the comparison unit 23 connects the reception control unit 24 and the transmission control unit 2 via the signal line 101.
7 is notified that the communication channel CHj or CHk of the other party has arrived. In response to the above notification, the reception control unit 24 takes in the contents C or Y of the communication channel CHj or CHk from the shift register 20 and sends it to the adder 25 via the signal line 105. Adder 2
5 adds the signal sent from the reception control section 24 and the signal output from the code decoding section 10 to the signal line 106 and outputs the result onto the signal line 107.
Furthermore, in response to the notification from the comparison unit 23, the transmission control unit 27 takes in the added signal output on the signal line 107 and sends it to the shift register 20.
As a result, the contents of the communication channel CHj or CHk are replaced with the above-mentioned added signal A+C or A, and the signal is sent from the shift register 20 to the transmission path 1b.

(c) Communication channels other than each communication channel CHi, CHj, CHk and communication channel CH1 for control signals
When CHm arrives, the comparator 23 determines that the communication channel CHm is transmission path 1.
When the synchronization unit 21 receives the notification that arrived from a,
Comparing the contents of the channel number memory 22 with the above notification, it is found that the communication channel CHm unrelated to the own station has arrived, and in this case, the comparison unit 23 does not instruct the reception control unit 24 and the transmission control unit 27 to do anything. is not issued, the arriving communication channel CHm passes through the shift register 20 as it is and is transferred to transmission path 1.
go out to b.

〔Effect of the invention〕

As described above, according to the voice switching system according to the present invention, each communication device has a function of adding voice signals, and the management device has a function of performing frame synchronization, control for specifying a communication channel, and control for specifying a communication channel. Since the configuration is equipped with a function to manage the system, there is no need for time division switches or trunks for conference calls in conventional voice switching systems of this type, and the simple configuration facilitates the expandability of the entire system. It has the feature of being able to Also,
Since normal calls and conference calls can be performed under the same control, this has the excellent effect of significantly reducing the burden on the management device.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing an example of a conventional voice exchange system, FIG. 2 is a configuration diagram of a frame used for transmitting voice signals in the voice exchange system of FIG. 1, and FIG. 4 is an explanatory diagram showing a conventional voice exchange method in normal telephone calls in the voice exchange system of FIG. 1; The figure is an explanatory diagram showing a conventional voice exchange method during a conference call in the voice exchange system of FIG. 1, and FIG. The explanatory diagram shown in FIG. 7 is a block diagram showing one embodiment of a telephone communication device in the voice exchange system of the present invention. 1 such as 1a to 1e... Transmission path, 2 such as 2a to 2c etc. 2... Telephone device, 3 such as 3a to 3c... Voice terminal device, 4... Management device, 5... Frame, 6...
Time division switch, 7... Trunk for conference call,
SYN……Synchronization pattern, CH1, CHi, CHj,
CH such as CHk, CHm, CHn... Communication channel,
10... Code decoding unit, 11... Sampling circuit, 1
2... Compressor, 13... Encoding circuit, 14... Decoding circuit, 15... Decompressor, 16... Interpolation filter, 20... Shift register, 21... Synchronization unit,
22...Channel number memory, 23...Comparison section,
24... Reception control unit, 25... Adder, 26...
Silent signal generator, 27... Transmission control section, 28...
Control signal control unit, 50, 51...Audio signal, 10
0 to 107...Signal lines. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1 A plurality of communication devices and at least one management device are connected in series in a ring through a common transmission path,
In a voice exchange system in which a frame constituted by a synchronization pattern and a plurality of communication channels arranged in a time-division manner is circulated on the transmission path, and communication is carried out between arbitrary communication devices using the communication channel. , the management device includes means for allocating a communication channel for the communication device to communicate with an arbitrary communication device via the transmission path, and means for communicating the allocated communication channel to the communication device, The communication device includes means for transmitting and receiving a control signal for specifying a communication channel to be used for a call with the management device, and a communication channel assigned to the own communication device from among the communication channels in the frame. means for selecting a communication channel assigned to the other party; and a means for selecting a communication channel assigned to the other party; and a means for selecting the communication channel by adding the audio signal in the communication channel assigned to the other party and the audio signal to be transmitted by the own communication device. and means for capturing an audio signal in a communication channel assigned to the local communication device, replacing the contents of the communication channel with an analog zero-level signal (silence signal), and transmitting the same. 1. A voice exchange system comprising: a voice exchange system, wherein conference calls can be made between the communication devices;