JPH05110711A - Data communication control method - Google Patents

Abstract

PURPOSE:To prevent a delay or a discordance in a control signal by transmitting the control signal and a commanding signal in a transparent manner among a data terminal equipment, a data interface unit and a ping-pong transmission circuit or the like. CONSTITUTION:In the data communication control method where a data terminal equipment is connected to a master equipment through a data interface unit having a data communication control microcomputer 32 and a ping-pong transmission circuit 30, a control data reception section 70 of the data communication control microcomputer 32 receives the control data to control selectors 34, 35 and sends the control signal among the data interface unit and the ping- pong transmission circuit 30 in a transparent manner. Moreover, the carrier detecting signal reception section 72 of the data communication control microcomputer 32 receives a carrier detecting signal sent in a transparent manner and controls the state of the data interface unit based on a commanding signal generated by the detecting signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data communication control method, and more particularly to a data communication control method in which a plurality of digital telephones are connected.

[0002]

2. Description of the Related Art Generally, in a data communication control device, a control signal is transmitted and received between a main device and a data interface unit to perform processing such as start and end of communication.
That is, at the start of communication, the main device transmits a "communication enabled" command signal to the data interface unit via the control channel, and at the end of communication, the data interface unit sends a "recovery request" command signal to the main device. The data is transmitted via the control channel, and conversely, the main device transmits a "disconnect" command signal to the data interface unit via the control channel to change the state of the data interface unit.

[0003]

In the data communication control device as described above, control signals are transmitted and received between the main device and the data interface unit, and processing such as communication start and end is performed. ) The timing of formation and disconnection of the control signal channel is delayed, and a situation may occur in which one data terminal ends the call but the other data terminal is in the call, or (2) the main device At the time of resetting, there is a problem that a state such as a difference in control signals may occur between the main device and the data interface unit.

Therefore, the present invention provides a data communication control method in which a control signal delay and a discrepancy between the main unit and the data interface unit are prevented.

[0005]

The present invention provides a data communication control method for connecting a data terminal to a main unit via a data interface unit having a data communication control microcomputer and a ping-pong transmission circuit. The control data receiving unit of the computer receives the control data and controls the selector to transmit the control signal transparently between the data terminal, the data interface unit, and the ping-pong transmission circuit,
Further, the carrier detection signal receiving unit of the data communication control microcomputer receives the carrier detection signal transmitted transparently, and controls the state of the data interface unit by a command signal created by the carrier detection signal. A method for controlling data communication is provided.

[0006]

[Operation] Data terminal, data interface unit,
Control signals and command signals are transparently transmitted between ping-pong transmission circuits and the like, and the states of the data interface unit are controlled by these control signals and command signals to prevent delay and discrepancy in the control signals.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the data communication control device of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an outline of the data communication control device of the present invention. This data communication control device 1
The main unit 11 of 0 includes a control unit 12 that performs call processing and communication path switching, a data highway 13 that transmits control data, a PCM highway 14 for time-division communication paths, and station line interface units 15a, ..., 15n. , Digital telephone interface unit 16a, ..., 16n
A standard telephone interface unit 17, a digital telephone interface unit 18, etc. are provided.

A microcomputer 19 such as a CPU and a time switch circuit 20 are built in the control unit 12, and control data from the microcomputer 19 is transmitted via the data highway 13 to the interface units 15a, ..., 16a ,. 17 and 18 and the time-division control data of the time switch circuit 20 is sent to the PC.
It is designed to be sent to each interface unit via the M highway 14.

, 15n of the main unit 11 is provided with a public telephone network for connecting the station lines 21a, ..., 21n, and the digital telephone interface units 16a ,.
22n and the data interface unit 23
, 23n and a plurality of digital telephones 24
, 24n are connected, the standard telephone interface unit 17 is connected to the modem 25, and the digital telephone interface unit 18 is connected to the data interface unit 26.

The data interface unit 23
, 23n are connected to data terminals 28a, ..., 28n via interfaces 27a, ..., 27n, such as RS-232D interfaces, and also to the modem 25 and data interface unit 26, for example, RS-232D. Interface 2 like interface
9 is connected.

The data communication control device 1 configured as described above
At 0, a keyboard (not shown) of the data terminal 28a or the like is pressed to generate a dial signal, and the digital telephone 24a of the data interface unit 23a, the digital telephone interface unit 16a, the data highway 13, the PCM highway 14, the digital telephone interface. The unit 16n and the digital telephone 24n of the data interface unit 23n are connected to make a call. Calls on other station lines 21a, 21n, etc. are also made in substantially the same manner.

FIG. 2 shows the telephones 22a, ..., 2 shown in FIG.
2n and the data interface unit 23a, ..., 23
FIG. 3 is a block diagram showing in detail one of the two, namely, the telephone 22a and the data interface unit 23a.

The telephone 22a and the data interface unit 23a include a ping-pong transmission circuit 30, a telephone control micro computer 31, a data communication control micro computer 32, selectors 33, 34 and 35.
Serial / parallel conversion circuits 36 and 37, serial / serial conversion circuits 38 and 39, and an RS-232D interface driver / receiver 40 are provided.

As shown in FIG. 3, the ping-pong transmission circuit 30 includes two B-channels (B-channel) having a speed of 64 kbps.
1 and B2 channels) and one D channel having a speed of 16 kbps, and a time division channel of 2B + D format is used, and ping-pong transmission of digital signals is performed between the data terminal 28a, the data interface unit 23a, and the main unit 11. Be done.

The ping-pong transmission circuit 30 receives the upstream data of each channel, synthesizes it into a data packet of 2B + D format, and transmits a digital signal to the digital telephone interface unit 16a.
1 and a 2B + D separation unit 42 which receives the downstream data packet of the 2B + D format from the digital telephone interface unit 16a and separates the data for each channel.

Here, the B1 channel is assigned to the transmission of voice data transmitted and received by the telephone 22a during the telephone call of the digital telephone 24a, and the B2 channel is assigned to the transmission of communication data transmitted and received during the data communication of the data terminal 28a. Further, the D channel data is assigned to the transmission of control data transmitted and received by the telephone control microcomputer 31 and the data communication control microcomputer 32. That is, the voice data is transmitted from the telephone set 22a, and the B1 channel upstream data B
The 1-IN is sent to the 2B + D creating unit 41, and the communication data is sent from the data terminal 28a during the data communication, and the driver / receiver 40, the selector 35, the serial / parallel conversion circuit 37, the parallel / serial conversion circuit 39, etc. Via the B2 channel upstream data B2-IN to the 2B + D creating section 41, and the control data is transmitted from the telephone control microcomputer 31 or the data communication control microcomputer 32, and the D channel via the selector 33. The 2B + D creating unit 41 is sent as the upstream data D-IN, and the 2B + D creating unit 4 is sent.
1 is made into a packet and sent to the digital telephone interface unit 16a via the transformer 43 and the like.

In addition, 2B from the digital telephone interface unit 16a via the transformer 43, the rectifier 44, etc.
The 2B + D packet sent to the + D creation unit 42 is B
1-channel downlink data B1-OUT, B2-channel downlink data B2-OUT and D-channel downlink data D-OUT are separated, and the data B1-OUT is telephone 2
2a, and the data B2-OUT is sent to the data terminal 28a via the serial / parallel conversion circuit 36, the parallel / serial conversion circuit 38, the selector 34 controlled by the data communication control microcomputer 32, the driver / receiver 40, and the like. Then, the data D-OUT is sent to the telephone control microcomputer 31 and the data communication control microcomputer 32.

The B2-channel upstream data B2-IN and the B2-channel downstream data B2-OUT are 8-bit serial data (64 kbps), respectively,
Of these, 6 bits are the communication data RD (48 kbps), the remaining 2 bits are the reception carrier detection signal CD (8 kbps) and the transmission enable signal CS (8 kbps) of the RS-232D interface, and the upstream data 2B-IN. The remaining 2 bits are the transmission request signal RS (8 kbps) and the transmission enable signal CS (8 kbps) of the RS-232D interface.

As shown in FIG. 2, the downlink data B2-OUT is first input to the serial / parallel conversion circuit 36, separated into communication data RD, a reception carrier detection signal CD and a transmission enable signal CS, and the communication data RD. Is input to the parallel / serial converter 38, converted into serial data of 48 kbps, and sent to the selector 34.

The transmission signal SD from the data terminal 28a is
Serial / parallel converter 37, parallel / serial converter 3 via driver / receiver 40 and selector 35
9, and the transmission request signal RS is
It is input to the receiver 40, the inverter 46, and the parallel / serial converter 39, and the parallel / serial converter 3
Both signals are combined by 9 and 8-bit upstream data 2B-IN is sent to the ping-pong transmission circuit 30.

Here, the telephone control microcomputer 31 controls the telephone 22a (for example, ringing a bell, turning on / off various displays, etc.) based on the D-channel downlink data D-OUT from the ping-pong transmission circuit 30. ) Is performed and control data corresponding to a signal (for example, a hook signal, a selection signal, etc.) from the telephone 22a is sent to the selector 33.

Under the control of the telephone control microcomputer 31, the selector 33 selects either the control data of the telephone control microcomputer 31 or the data communication control microcomputer 32, and selects this control data. It is sent to the ping-pong transmission circuit 30 as the upstream data D-IN of the D channel.

The telephone control microcomputer 31 is
When transmitting the control data, the selector 33 is controlled to select its own transmission control data, and the control data transmission is prohibited to the data communication control microcomputer 32.

Therefore, the data communication control microcomputer 32 sends the control data only while the telephone control microcomputer 31 does not send the control data.
Then, the control data of the D channel is sent to the selector 3
3. Send to the digital telephone interface unit 16a of the main device 11 via the ping-pong transmission circuit 30.

FIG. 4 is a block diagram showing the internal structure of the data communication control microcomputer 32 shown in FIG. That is, in the data communication control microcomputer 32, a D channel sending unit 50 that sends the D channel upstream data D-IN to the ping-pong transmission circuit 30 and a D channel receiving unit 51 that receives the D channel downstream data D-OUT are provided. It is provided. The output signal of the D channel receiver 51 is sent to the tristate buffer 52 and the address analyzer 53. The control data subjected to the address analysis by the address analysis unit 53 is sent to the tristate buffer 52, and is sent to the tristate buffer 52.
It is used as a control signal for the buffer 52. The output signal of the tri-state buffer 52 is sent to the data analysis unit 54 and data analysis is performed.

This data analysis output signal is sent to the inverter 5
5, the called display control unit 56, the data set ready control unit 57, and the data control unit 58.

The inverter 55 inversely converts the data analysis output signal, and the inverse conversion data analysis output signal is transmitted from the tristate buffer 59 provided on the output side of the data control unit 58 and the driver / receiver 40. The signal is sent to the tri-state buffer 60 which receives SD and is used as a control signal for the tri-state buffer 59 and the tri-state buffer 60.

When the called display control unit 56 receives the data analysis output signal, the called display signal CI is generated, and when the data set ready control unit 57 receives the data analysis output signal, the data set ready signal CI. DR is generated,
Each is sent to the data terminal 28a via the driver / receiver 40 and controls the data terminal 28a.

The transmission data SD sent from the data terminal 28a via the driver / receiver 40 is sent to the data monitoring unit 61 via the tristate buffer 60, and
The restoration request signal ER is sent to the restoration monitoring unit 62. When the transmission data SD is monitored, a data monitoring control signal is sent to the data creating section 63, and when the recovery request signal ER is monitored, the recovery request signal ER is sent to the data creating section 63 and these are sent. Data SD and restoration request signal ER
Are synthesized and sent to the tristate buffer 64.

The tri-state buffer 64 is controlled by a control signal of the telephone control microcomputer 31,
The data is sent to the D-channel sending unit 50 and sent to the ping-pong transmission circuit 30 as D-channel upstream data D-IN via the selector 33.

In this way, the downlink data D-OUT of the D channel sent from the ping-pong transmission circuit 30 is received, the data is analyzed, and the called display signal CI, the data set ready signal RD, and the communication data signal RD are received. Is separated into
It is sent to the data terminal 28a via the driver / receiver 40, and the transmission data signal S from the data terminal 28a is transmitted.
Data is created by D and the recovery request signal ER, and ping-pong transmission circuit 3 is used as the upstream data D-IN of the D channel.
0 to control the ping-pong transmission circuit 30.

FIG. 5 shows another example of control of the data communication control microcomputer 32 of FIG. 4, in which the data communication control microcomputer 32 causes the ping-pong transmission circuit 30 to output the D channel downlink data D-OUT. In response to this, it controls the selectors 34, 35 and the like, and sends it to the ping-pong transmission circuit 30 as the upstream data D-IN of the D channel. That is, the data communication control microcomputer 32 is provided with the control data receiving unit 70 which receives the control data of the downlink data D-OUT of the D channel from the ping-pong transmission circuit 30.

This control data is a communication request signal (R
S) or a communication end signal (end call), the control data receiving unit 70 generates an output signal corresponding to the control data. When the control data receiving unit 70 receives the communication request signal (RS), it is sent to the selector switching unit 71 and the carrier detection signal receiving unit 72.

The selector switching unit 71 causes the communication request signal (R
S), a select signal is generated and the selector 3
4, 35 to control the communication signal to the ping-pong transmission circuit 30,
The selection control is performed so that the data is transparently transmitted to the data terminal 28a via the serial / parallel converter 36, the parallel / serial converter 38, the selector 34, and the driver / receiver 40.

The communication signal is selectively controlled so as to be transparently transmitted to the ping-pong transmission circuit 30 via the data terminal 28a, the driver / receiver 40, the selector 35, the serial / parallel converter 37, and the parallel / serial converter 39. ..

As a result, the state of the data interface unit 23a is controlled even if there is no control signal.

When the carrier detection signal receiving section 72 receives the communication request signal (RS), the carrier detection signal receiving section 72 is activated to monitor ON / OFF of the carrier detection signal CD. In this monitoring, when the carrier detection signal CD is on, the command generating section 73 generates a control signal during communication. This control signal is sent to the command sending unit 74, and the command signal is sent to the data terminal 28a via the driver / receiver 40. When the data terminal 28a receives the command signal, a transmission request signal RS is generated, and the transmission request signal RS is transmitted to the driver / receiver 40 and the inverter 4
6. The data is transparently transmitted to the ping-pong transmission circuit 30 by the negative theory via the parallel-serial converter 39, and the state of the data interface unit 23a is controlled and sent to the main device 11.

When the carrier detection signal CD is off, the command generation unit 73 generates a control signal for the restoration request signal ER. The control signal ER is sent to the command sending unit 74.
And is sent to the data terminal 28a via the driver / receiver 40 to restore the data terminal 28a.

When the control data receiving section 70 receives the call termination signal, the call termination signal is sent to the selector switching section 71. When the selector switching unit 71 receives the call end signal, it generates a select signal to control the selectors 34 and 35.
This control is different from the signal during communication, and the communication signal transmitted to the data terminal 28a via the ping-pong transmission circuit 30, the serial / parallel converter 36, the parallel / serial converter 38, the selector 34, and the driver / receiver 40 is transmitted. Data terminal 28a, driver / receiver 40, selector 35, serial / parallel converter 3
7. The communication signal transmitted to the ping-pong transmission circuit 30 via the parallel / serial converter 39 is stopped.

As a result, the data interface unit 23a controls the state of only the data communication control microcomputer 32.

In this way, communication data is transmitted from the main unit 1 by the control data received by the control data receiving section 70 and the carrier detection signal received by the carrier detection signal receiving section 72.
1, the ping-pong transmission circuit 30, the data interface unit 23a and the data terminal 28a are transparently transmitted, and the state of the data interface unit 23a is controlled without a control signal, and the main device 11, the ping-pong transmission circuit 30, and the data interface unit 2 are controlled.
3a and the data terminal 28a can be connected without any difference.

FIG. 6 shows the structure of the PCM highway in the main unit 11, and the PCM highway is connected to the ping-pong transmission circuit 30.
The time switch circuit 20 is connected via the M highway (PHIN) 14, and the time switch circuit 20 has a tri-state buffer 75 and an external pull-up resistor 76.
The PCM highway (PHOUT) 14 is connected to the ping-pong transmission circuit 30 via the downlink PCM highway (PHOUT) 14 provided to change the contents of the PCM highway (PHOUT) 14 to obtain a 3-state output from the PCM highway (PHOUT) 14. It is in a high impedance state until the path is formed.

The data terminal 28a, the data interface unit 23a, the digital telephone 24a, the digital telephone interface unit 16a, the data highway 13, the PCM highway 14, the digital telephone interface unit 16n, and the digital telephone 24n of the data interface unit 23n are connected to each other to extend the extension. In order to make a call, a command signal such as "call", "call", "dial signal", "disconnection request", "end call", etc. is sent using the transmission data SD and communication data RD to the data terminals 28a, ..., 28n.
And the digital telephone interface unit 16a, ...
16n, when the call connection procedure, the recovery procedure is carried out, or when the half-duplex communication is carried out, the state of the carrier detection signal transmitted from the partner data interface unit 23n is constantly monitored, and the carrier detection signal is sent. When is on, the call is in progress, and when the carrier detection signal is off, the call is terminated and processing is performed.

FIG. 7 shows the configuration of the digital telephone interface unit 16a of the main unit 11 in FIG.
The digital telephone interface unit 18 for connecting the data interface unit 26 has the same configuration.

The digital telephone interface unit 16a is provided with eight ping-pong transmission circuits 80 for connecting a digital telephone, and is connected to each data eater interface unit 23a via a data transformer 81 for each digital transmission. 2B + D between these
Ping-pong transmission of a time division channel of the form is performed.
These ping-pong transmission circuits 80 have the same configuration as the ping-pong transmission circuit 30 in the data eater interface unit 23a shown in FIG.
Operates in slave mode, whereas ping-pong transmission circuit 80 operates in master mode. In other words, the ping-pong transmission circuit 80 in the master mode has the initiative in the bucket transmission of the ping-pong transmission.

The time slot assigner 82 receives the frame synchronization signal and the clock signal from the PCM highway 14, transmits and receives the upstream and downstream data of the B channel, and informs each ping-pong transmission circuit 80 and the like at a timing.

Each ping-pong transmission circuit 80 directly accesses the PCM highway 14 at the time designated by the time slot assigner 82 to send and receive the upstream and downstream data at a speed of 2.048 Mpbs.

Microcomputer 8 for control data communication
3 monitors the D channel data (control data) transmitted and received by each ping-pong transmission circuit 80, and communicates with the control unit 12 through the data highway 13 of the control data.

FIG. 8 shows the structure of the data interface unit 26 shown in FIG. The data interface unit 26 includes a ping-pong transmission circuit 90, a data communication control microcomputer 91, selectors 92 and 93,
Serial / parallel conversion circuits 94 and 95, parallel / serial conversion circuits 96 and 97, a driver / receiver 98 for the RS-232 interface, and the like are provided, and are similar to the data interface unit 23a described in FIG. However, the data interface unit 23a
Is set to the modem mode for the data terminal 28a, whereas the data interface unit 26 is set to the terminal mode for the modem 25.

That is, the RS-232D interface 2
The direction of signal line 9 is reversed.

Further, since the data interface unit 26 is not built in the digital telephone 24a, the B1 channel for voice data transmission is unnecessary, and the upstream control data for telephone control and data communication control is selected. There is no selector to do it.

FIG. 9 shows the structure of the standard telephone interface unit 17. The standard telephone interface unit 17 is provided with a call signal transmission circuit 100, and is a circuit for transmitting a call signal (16 Hz AC signal) supplied from the call signal generation source 101 to the modem 25. Also, this standard telephone interface unit 1
7, a DC power supply circuit 102 is provided, which is a circuit for applying a specified DC voltage to the modem 25, inverting its polarity, and detecting opening / closing of a DC loop. Further, the standard telephone interface unit 17 is provided with a dial detector 103, and a dial pulse is detected.

This standard telephone interface unit 1
7 is provided with a codec unit 105 via a transformer 104, the voice signal is A / D converted and D / A converted, and P is transmitted at a time designated by a time slot assigner 106.
Transmission and reception of voice data with the CM highway 14 is performed.

This standard telephone interface unit 1
The control data communication microcomputer 107 provided in FIG. 7 sends a calling signal to the calling signal sending circuit 100, the DC power supply circuit 102, the dial detecting unit 103, etc., stops the calling signal, monitors the opening and closing of the DC loop, controls the reversal of the polarity, and dials. It monitors the pulse detection result and communicates control data with the control unit 12 through the data highway 13.

FIG. 10 shows the office line interface unit 1
The structure of 5a is shown.

The station line interface unit 15a includes a calling signal detection circuit 110 and a polarity inversion detection circuit 11.
1, a DC loop circuit 112, a codec section 113, a time slot assigner 114, a control data communication microcomputer 115, and the like.

The call signal detection circuit 110, the polarity reversal detection circuit 111, the DC loop circuit 112, etc. are connected to the station line 21a of the public telephone network, and the detection of the call signal from the station line 21a, the detection of the polarity reversal, and the DC loop. It opens and closes, releases, and sends dial pulses.

The codec section 113 performs A / D conversion and D / A conversion on the audio signal, and the DC loop circuit 112.
By forming a DC loop in the office line 21a, the AC line is AC-coupled to the office line 21a.

Several sets of the calling signal detection circuit 110, the polarity reversal detection circuit 111, the DC loop circuit 112, and the codec section 113 are mounted for each station line interface unit 15a.

The time slot assigner 114 uses the predetermined time slot address for each codec section 113 and the frame synchronization signal and clock signal from the PCM highway 14 to cause each codec section 113 to communicate with the PCM highway 14 and voice data. The timing of transmitting and receiving is determined and notified to each codec section 113.

Each codec section 113 transmits / receives voice data to / from the PCM highway 14 at the time designated by the time slot assigner 114.

Microcomputer 1 for control data communication
Reference numeral 15 is for monitoring the detection signals of the ringing signal detection circuit 110 and the polarity reversal detection circuit 111, controlling the DC loop circuit 112, detecting the ringing signal with the control unit 12 through the control data highway 13, the polarity reversal detection, and the opening / closing of the DC loop. , Sends and receives control data related to sending dial pulses.

The station line interface unit 15a,
The microcomputer 19 in the control unit 12 for controlling the digital telephone interface unit 16a, the standard telephone interface unit 17, etc. is configured as shown in FIG.

The microcomputer 19 performs call processing and exchange control of the key telephone device 10 as a whole. That is, in the microcomputer 19,
Data receiving unit 120 connected to the data highway 13
Are provided to accept control data from each part of the system. This control data is sent to the data receiving section 120.
Are decoded by the local line 21.
If it is an incoming signal from a, the modem selection unit 121 is activated and the control data written in the modem busy table 122 is read. Information such as whether the modem 25 is vacant or busy is written in the modem busy table 122 in advance. The modem selection unit 121 refers to the information in the modem busy table 122 and sets one modem 2 in an idle state.
5 is selected and sent to the command sending unit 123.
The command sending unit 123 sends the incoming data to the standard telephone interface unit 17 via the data highway 13 to call the selected modem 25.

The reception at the data receiving unit 120 is performed by the modem 25.
If it is a response of the
23 and the time switch control unit 124. Then, the command transmission unit 123 instructs the office line interface unit 15a to close the incoming loop (supplement of the office line), and the time switch control unit 124 controls the time switch circuit 20 to make the office line interface. The unit 15a and the standard telephone interface unit 17 are connected. This establishes a communication path between the modem 25 and the calling data device. Also, the modem visitor table 12
In No. 2, since the modem 25 is free, it is rewritten as busy.

The decoding result of the data receiving section 120 is
In the case of designating the extension number input to the modem 25 through the communication path from the calling side data device, the data interface unit selection unit 125 is activated and the control data written in the data interface unit visit table 126 is read. .. The data interface unit visit table 126 includes each digital telephone 24.
a, ..., 24n data interface unit 23
The states of a, ..., 23n (empty or busy) are described.

Data interface unit selection section 12
5 reads out the state of one data interface unit 23a specified by the extension number from the data interface unit busy table 126, and if it indicates a vacancy, the data interface unit 23a
The extension number is notified to the command transmitting unit 127. Then, the command sending unit 128 sends the incoming data to the data interface unit 23a to call the data terminal 28a. Further, in the data interface unit busy table 126, the state of the data interface unit 23a is rewritten from free to busy.

The decoding result of the data receiving unit 120 is the data interface unit 2 for the incoming data.
3a, the command transmitting unit 12
8 and the time switch sending unit 129 are notified.

The command transmitting unit 128 transmits a modem connection command indicating the connection between the data terminal 28a and the modem 25 to the data interface unit 23a and the data interface unit 23n, and the time switch transmitting unit 129 causes the time switch circuit 20 to operate. By controlling, the data interface unit 23a and the digital telephone interface unit 18 are connected.

As a result, the data terminal 27a and the modem 2
5, the communication path is established, and as a result, the data communication is transmitted, and data communication between the data terminal 28a and the calling side data device through the public telephone network is started.

The decoding result in the data receiving section 120 is
When the data interface unit 23a after the start of the data communication is off-hook, this is notified to the command sending unit 130 and the time switch control unit 131.

The command transmitting section 130 instructs the station line interface unit 15a to release the straight line loop of the station line 21a, and the data interface unit 2
Disconnection data indicating disconnection of the communication path is sent to 3a.
The time switch control unit 131 includes the time switch circuit 2
0 is controlled to disconnect both communication paths between the modem 25 and the office line interface unit 15a and between the modem 25 and the data interface unit 23a.

This completes the data communication. In addition, the modem 25 read by the modem busy table 122
Status and the data interface unit busy table 126 reads the data interface unit 2
The state of 3a is rewritten from busy to empty.

[0075]

As described above, according to the data communication control method of the present invention, the control data received by the data communication control microcomputer and the carrier detection signal are transparent to the ping-pong transmission circuit, the data interface unit and the data terminal. Since it is transmitted, the state of the data interface unit can be controlled without the control signal for controlling the data interface unit.

As a result, the main device, the ping-pong transmission circuit,
It is possible to prevent a discrepancy in the connection of the data interface unit, the data terminal and the like.

[Brief description of drawings]

FIG. 1 is a block diagram showing an overall outline of a data communication control method.

FIG. 2 is a block diagram showing an outline of the digital telephone shown in FIG.

FIG. 3 is a block diagram showing an outline of the ping-pong transmission circuit of FIG.

4 is a block diagram showing an outline of a first operation of the microcomputer for controlling data communication in FIG.

5 is a block diagram showing an outline of a second operation of the data communication control microcomputer of FIG.

6 is a block diagram illustrating transmission of control data between the ping-pong transmission circuit of FIG. 2 and the time switch circuit of FIG.

FIG. 7 is a block diagram showing an outline of the digital telephone interface unit of FIG.

FIG. 8 is a block diagram showing an outline of the data interface unit of FIG.

FIG. 9 is a block diagram showing an outline of the standard telephone interface unit of FIG.

10 is a block diagram showing an outline of the office line interface unit of FIG.

11 is a block diagram showing an outline of the microcomputer shown in FIG.

[Explanation of symbols]

 10 data communication control device 11 main unit, 12 control unit 13 data highway 14 PCM highway 15a station line interface unit 16a digital telephone interface unit 17 standard telephone interface unit 18 digital telephone interface unit 19 microcomputer 20 time switch circuit 21a station line 22a telephone 23a data interface unit 24a digital telephone 25 modem 26a data interface unit 28a data terminal 30 ping-pong transmission circuit 31 telephone control microcomputer 32 data communication control microcomputer 41 2B + D creation unit 42 2B + D separation unit 50 channel transmission unit 51 channel reception unit 70 Control data receiver 71 Selector switching Part 72 Carrier detection signal receiving part 80 Ping-pong transmission circuit 82 Time slot assigner 83 Control data communication microcomputer 90 Ping-pong transmission circuit 91 Data communication control microcomputer 105 Codec part 106 Time slot assigner 107 Control data communication microcomputer 113 Codec section 114 Time slot assigner 115 Control data communication microcomputer 120 Data receiving section 121 Modem selecting section 122 Data interface unit selecting section

Claims (1)

[Claims] 1. A data communication control method for connecting a data terminal to a main unit via a data interface unit having a data communication control microcomputer and a ping-pong transmission circuit, wherein a control data receiving section of the data communication control microcomputer controls. Upon receiving data, the selector is controlled, the control signal is transparently transmitted among the data terminal, the data interface unit, and the ping-pong transmission circuit, and the carrier detection signal receiving unit of the data communication control microcomputer is transparent. Received the carrier detection signal transmitted to
A data communication control method characterized in that the state of the data interface unit is controlled by the command signal created in this way.