JP2575514B2 - Data communication device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a data communication device for exchanging data between a central processing unit and a terminal device in a computer, for example.

2. Description of the Related Art FIG. 3 is a block diagram schematically showing a transmission / reception mechanism of one data processing device in a conventional data communication device, for example, a central processing unit 1 of a computer.

When data is exchanged between the central processing unit 1 and another data processing device, for example, a terminal device, the central processing unit 1
A modem for modulating the transmission data output from the main body of the communication device and transmitting the data to the communication line, and demodulating the reception data transmitted from the terminal device via the communication line. As shown in FIG. 3, there are two modes, a case where the modem 2a is built in the central processing unit 1, and a case where the modem 2b is installed outside.

Therefore, in the conventional data communication device, the built-in modem 2a is connected to the main body of the central processing unit 1 via a dedicated transmission line 3a, and is connected to a modem 2b provided outside the central processing unit 1. A connector 4 for measuring is provided in the central processing unit 1. The connector 4 is connected to the main body of the central processing unit 1 via another transmission line 3b, and the external modem 2b is connected to the main body of the central processing unit 1 via the connector 4 and the transmission line 3b. .

In the data communication device described above, two types are used depending on whether the internal modem 2a is used or the external modem 2b is used.
Either one of the transmission lines 3a and 3b is switched and connected to the main body of the central processing unit 1 by software.

However, in the above-described conventional data communication device,
Two transmission lines 3a and 3b are required to properly use the built-in modem 2a and the external modem 2b, and software processing is required to switch between the transmission lines 3a and 3b. Had a point.

Accordingly, it is an object of the present invention to provide a data communication apparatus which can use only one transmission path to selectively use a built-in modem and an external modem, and does not require transmission path switching processing by software. .

Means for Solving the Problems The present invention modulates data output from a first data processing device main body by a modulation / demodulation device, transmits the modulated data to a second data processing device via a communication line, and transmits the data to a second data processing device. A data communication device which demodulates the data transmitted from the communication line via the communication line and inputs the data to the first data processing device main body. State, the first and second input terminals, and when set to the selected state, the input from the first input terminal is sent to the first data processing device main body, and the state is set to the non-selected state. A multiplexer having an output terminal for sending an input from the second input terminal to the first data processing device main body when set, and switching between a selected state and a non-selected state provided in the first data processing device An input terminal for inputting transmission data output from the first data processing device main body, a first output terminal for outputting transmission data input to the input terminal when set to the selected state, A demultiplexer having a second output terminal for outputting transmission data input to an input terminal when set to a non-selection state; and a built-in modem when the modem is incorporated in a first data processor. Connected to the first input terminal of the multiplexer, and connected to the first input terminal of the multiplexer, and connected to the first input terminal of the multiplexer.
And a connector for a built-in modulator / demodulator for setting a multiplexer and a demultiplexer to a selected state, the output terminal being connected to a transmission data modulation input terminal of the built-in demodulator, and the modem being provided outside the first data processor. Connected to the external modulator / demodulator for outputting demodulated received data, the output terminal of the external modulator / demodulator is connected to the second input terminal of the multiplexer, and the second output terminal of the demultiplexer is connected to the transmission data of the external modem. A data communication device comprising: a connector for an external modem connected to a modulation input terminal.

According to the present invention, the data processing device main body and the built-in modem can be connected to each other by the multiplexer and the demultiplexer interposed between the connector connected to the built-in modem and the connector connected to the external modem and the data processing device main body. The state can be switched between the state of signal transmission / reception by the apparatus and the state of signal transmission / reception by the data processing apparatus main body and the external modulation / demodulation apparatus, and the switching can be completed by one transmission line. Further, since the switching is automatically performed by attaching / detaching the built-in modulation / demodulation device, the switching process by software becomes unnecessary.

Embodiment FIG. 1 is a block diagram showing a schematic configuration of a transmission / reception mechanism on one central processing unit 11 side of a data communication apparatus of a data communication apparatus according to an embodiment of the present invention, for example, a computer.

The multiplexer 12 has one output terminal 1Ya, two input terminals 1Aa and 1Ba, and a select terminal Sa, and performs a first input under a state where a low-level selection signal is input to the select terminal Sa. The signal input to the terminal 1Aa is output from the output terminal 1Ya, and the signal input to the second input terminal 1Ba under the condition that the high-level non-selection signal is input to the select terminal Sa is output to the output terminal. The output terminal 1Ya is connected to the main unit of the central processing unit 11 via a transmission line 14.

The demultiplexer 13 has one input terminal 1Yb, two output terminals 1Ab and 1Bb, and a select terminal Sb. The input terminal 1Yb is in a state where a low-level selection signal is input to the select terminal Sb. Is output from the first output terminal 1Ab, and the signal input to the input terminal 1Yb is input to the second output terminal 1Bb in a state where the non-selection signal of the select terminal Sb high level is input. The output terminal 1Yb has a function of outputting from the transmission line 14 described above.
Is connected to the main body of the central processing unit 11 via the.

The internal modem connector 15 connects the central processing unit 11 to the modem.
A connector connected to the built-in modem 17a when the built-in modem 17a is built-in, the output terminal of the built-in modem 17a outputting modulated reception data being connected to the first input terminal 1Aa of the multiplexer 12, 13, the first output terminal 1Ab is connected to the transmission data modulation input terminal of the built-in modem 17a, and the low level is applied to the select terminals Sa and Sb of the multiplexer 12 and the demultiplexer 13 under the connection state with the built-in modem 17a. Is a circuit having a function of giving a selection signal of

The external modem connector 16 is a connector connected to the external modem 17b when the modem 17b is provided outside the central processing unit 11, and connects an output terminal of the external modem 17b for outputting modulated reception data to the multiplexer 12b. Second
And a function of connecting the second output terminal 1Bb of the demultiplexer 13 to the transmission data modulation input terminal of the external modem 17b.

FIG. 2 is a circuit diagram showing a connection structure between the internal modem connector 15 and the connector 18 on the internal modem 17a side. The terminal 19a of the built-in modem connector 15 is connected to a positive potential voltage source 22 via a pull-up resistor 21 and is also connected to each of the SELECT terminals Sa and Sb of the multiplexer 12 and the demultiplexer 13, respectively. One terminal 20a is grounded.

In contrast, the connector 18 on the internal modem 17a side
The terminal 19b corresponding to the terminal 19a and the terminal 20b corresponding to the terminal 20a are short-circuited, and the internal modem connector 15 and the connector 18 on the internal modem 17a side are connected, that is, between the terminals 19a and 19b. And between terminals 20a and 20b
Each of the select terminals S of the multiplexer 12 and the demultiplexer 13 is connected under the state shown by the broken line in FIG.
A low level selection signal is supplied to a and Sb, and a high level non-selection signal is supplied in a state where the internal modem 17a is disconnected from the internal modem connector 15.

Next, transmission / reception operations of the central processing unit 11 in the data communication device will be described.

When data communication is performed using the built-in modem 17a, that is, when the built-in modem 17a is connected to the built-in modem connector 15, the selector terminals of the multiplexer 12 and the demultiplexer 13 are connected according to the connection structure shown in FIG.
Sa and Sb are supplied with a low-level selection signal.

As a result, the transmission data input from the main body of the central processing unit 11 to the input terminal 1Yb of the demultiplexer 13 via the transmission line 14 is transmitted to the first output terminal 1A of the demultiplexer 13.
It is output from b and input to the transmission data modulation input terminal of the internal modem 17a via the internal modem connector 15. The input transmission data is modulated by the built-in modem 17a and transmitted to another data processing device such as a terminal device via a communication line (not shown).

In addition, a built-in modem 17a is transmitted from a terminal device via a communication line.
Modulated data sent to the internal modem 17
The signal is demodulated by a, and is input from the output terminal for received data to the first input terminal 1Aa of the multiplexer 12 via the built-in modem connector 15. The received data is sent to the main body of the central processing unit 11 via the output terminal 1Ya of the multiplexer 12 and the transmission path 14.

On the other hand, when data communication is performed using the external modem 17b, that is, the external modem 17 is connected to the external modem connector 16.
b is connected and the internal modem 17a is disconnected from the internal modem connector 15, the multiplexer 12 and the demultiplexer are changed from the connection structure shown in FIG.
A high-level non-selection signal is supplied to each of the thirteen selector terminals Sa and Sb.

As a result, the transmission data input from the main body of the central processing unit 11 to the input terminal 1Yb of the demultiplexer 13 via the transmission line 14 is transmitted to the second output terminal 1B of the demultiplexer 13.
The signal is output from the external modem 17b and is input to the transmission data modulation input terminal of the external modem 17b via the external modem connector 16. The input transmission data is modulated by the external modem 17b and transmitted to another data processing device such as a terminal device via a communication line (not shown).

In addition, the external modem 17b is connected to the terminal device via a communication line.
The modulated data sent to the external modem 17
The signal is demodulated by b, and is input from the output terminal for received data to the second input terminal 1Ba of the multiplexer 12 via the connector 16 for external modem. The received data is sent to the main body of the central processing unit 11 via the output terminal 1Ya of the multiplexer 12 and the transmission path 14.

Effect of the Invention As described above, according to the data communication device of the present invention, the multiplexer and the demultiplexer are provided between the connector connected to the built-in modem and the connector connected to the external modem, and the data processing device main body. By intervening, it is possible to switch between a state of signal transmission and reception between the data processing device main body and the built-in modem, and a state of signal transmission and reception between the data processing device main body and the external modulation and demodulation device. With only one transmission path,
In addition, the switching is automatically performed by attaching and detaching the built-in modulation / demodulation device, so that the switching process by software becomes unnecessary.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of a transmission / reception mechanism in one data processing device in a data communication apparatus according to an embodiment of the present invention, and FIG. 2 is a connector for a built-in modem and a built-in modem in the transmission / reception mechanism. FIG. 3 is a block diagram showing a connection structure with a side connector, and FIG. 3 is a block diagram showing a schematic configuration of a transmission / reception mechanism in one data processing device in a conventional data communication device. 11 Central processing unit, 12 Multiplexer, 13 Demultiplexer, 14 Transmission line, 15 Connector for internal modem, 16 Connector for external modem, 17a Internal modem, 17b External modem

Claims (1)

(57) [Claims] A data output from a main body of a first data processing device is modulated by a modem and transmitted to a second data processing device via a communication line, and is transmitted from the second data processing device via a communication line. In a data communication device in which transmitted data is demodulated by the modulation and demodulation device and input to the first data processing device main body, the data communication device is provided in the first data processing device and has a setting for switching between a selected state and a non-selected state. It is possible to send an input from the first and second input terminals to the first data processing apparatus main body when set to the selected state and to set the second input terminal to the second data processing apparatus when set to the non-selected state. A multiplexer having an output terminal for sending an input from the input terminal of the first data processing device to the first data processing device main body; and a switch provided between the first data processing device and being capable of switching between a selected state and a non-selected state. No An input terminal for inputting transmission data output from the data processing device body, a first output terminal for outputting transmission data input to the input terminal when set to the selected state, and when set to a non-selected state A demultiplexer having a second output terminal for outputting transmission data input to an input terminal; and a demodulated reception data connected to the internal modulation / demodulation device when the modulation / demodulation device is incorporated in the first data processing device. Is connected to a first input terminal of the multiplexer, a first output terminal of the demultiplexer is connected to a transmission data modulation input terminal of the built-in demodulator, and the multiplexer and the demultiplexer are connected to each other. A connector for a built-in modem that is set to a selected state, and an external when the modem is provided outside the first data processing device. An output terminal of an external modulation / demodulation device connected to the demodulation device and outputting demodulated received data is connected to a second input terminal of the multiplexer, and a second output terminal of the demultiplexer is connected to a transmission data modulation input terminal of the external modulation / demodulation device. And a connector for an external modem connected to the data communication device.