KR900007677B1 - Arrangement for selecting variable communication systems - Google Patents

Abstract

The circuit for transmitting the data regardless the computer type equips a RS232C type (1), a RS422 type (2), and a current loop type transmission circuits. Each circuit comprises a line driver and a line receiver placed between a connector (CON) connected to a MODEM and a microprocessor (MP). A transmission data output terminal (TDD) of the microprocessor is connected to transmission data input terminals (TDI1-3) corresponding to each transmission type through line drivers (U1,U7,U9). A receiving data input terminal (RDI) is connect to each receiving data output terminal (RDO1-3) connected to an AND gate (AND) through line receivers (U3,U6,U10).

Description

Multifunctional Transmission Control Circuit

1 is a circuit diagram of the present invention.

* Description of the main parts of the drawings

1: RS-232C transmission part 2: RS-422 transmission part

3: Current loop transmission unit U1, U7, U9: Line driver

U2, U3, U6, U10: Line receiver AND: And gate

MP: Microprocessor TDO: Transmission Data Output Terminal

TDI1 to TDI3: Transmission data input terminal RDI: Reception data input terminal

DO1 to RDO3: Receive data output terminal CON: Connector

RTS, DTR, CTS, DCD, DSR, C / L: Various control signals

[Industrial use]

The present invention relates to a circuit that allows data to be transmitted and received between a modem, a computer, and a terminal according to a transmission method, and in particular, each transmission method is selected according to a data transmission method between devices, thereby enabling data to be transmitted to each other. It relates to a multi-function transmission control circuit.

As the number of information communication between computer and CRT terminal, facsimile, teletex, videotex and workstation increases, the use of modem, the basic equipment of information transmission, is increasing. Various methods of transmission are used to suit the needs.

Among them, the maximum transmission speed is 20Kbit / sec and the RS-232C method transmits data from 1 modem, which is about 15 feet, to the main computer, and the maximum transmission speed is 10Mbit / see, and the transmission distance is about 50 RS-422 method, which is a method of transmitting from the modem, which is a bit, to the main computer, and the transmission speed and distance are superior to those of the RS-232C method and the RS-422 method described above. The current loop method that can be used by the user has been introduced.

However, since the transmission methods are preset in one type according to the modem, it is inconvenient to replace the computer with the corresponding transmission method when using one computer for a modem that uses a different transmission method. Will be.

[Purpose of invention]

Thus, the present invention was invented to solve the above inconvenience. The RS-232C method, which is the most commonly used in computer design, is fixed and installed, and then the RS-422 and current loop circuits are installed by connecting the receive data transmission terminal with an end gate. It is an object of the present invention to provide a multi-function transmission control circuit capable of transmitting data by one computer without changing the model.

[Configuration of Invention]

The multi-function transmission control circuit according to the present invention for achieving the above object is an RS-232C type line driver U1 and a line receiver U3 between a connector CON and a microprocessor MP to be connected to a modem. RS-232C transmission unit (1) consisting of the RS-422 transmission unit (2) consisting of a line driver (U7) and a line receiver (U6) for the RS-422 method, and a current loop method A current loop type transmission unit 3 including a line driver U9 and a line receiver U10 is provided, and a transmission unit 1 according to the above schemes is provided in the transmission data output terminal TDD of the microprocessor MP. The transmission data input terminals TDI1-TDI3 of the corresponding method of the connector CON are connected to each other via the line drivers U1, U7, U9 of ˜3), and each of the received data output terminals of the connector CON is connected. RDO1-RDO3 have input terminals of the AND gate AND through the line receivers U3.U6 and U10 of the corresponding method, respectively. Power supply voltage Vcc is connected to the connection point between the line receiver U6 and the AND gate AND and the connection point between the line receiver U10 and the AND gate AND through resistors R1 and R2, respectively. Being connected. A reception data input terminal RDI of the microprocessor MP is connected to an output terminal of the AND gate AND to transmit or receive all data regardless of the type of computer.

Example

Hereinafter, an embodiment according to the present invention will be described with reference to the drawings. FIG. 1 is a circuit diagram showing a multi-function transmission control circuit according to the present invention having the above-described configuration. In FIG. 1, MP is a microprocessor used as a communication chip such as IC number 6551, and reference numeral 1 is RS-. RS-232C transmission unit including a 232C-type line driver (U1, transmitter) and a line receiver (U3). Reference numeral 2 denotes an RS-422-type line driver (U7) and a line receiver (U6). RS-422 type transmission unit, and reference numeral 3 is a current loop type transmission unit including a current loop type line driver U9 and a line receiver U10.

Here, the line drivers U1, U7, and U9 are transmitters, for example, IC numbers 1488, 26LS31, and HP4100 used in the RS-232C method, the RS-422 method, and the current loop method, respectively, which are microprocessors. Communication data from (MP) is converted to each communication method and transmitted to the connector CON side.

In addition, the line receivers U3, U6, and U10 are receivers, for example, IC numbers 1489, 26LS32, and HP4200 used in the RS-232C method, the RS-422 method, and the current loop method, respectively. Communication data from the modem MODEM applied through the CON is applied to the microprocessor MP side.

Reference numeral U2 denotes a line receiver for which a control signal from a modem is applied to the microprocessor (MP) side, for example, IC number 1489, which is commonly used for RS-232C, RS-422, and current loop methods. do.

Also, CON is a connector for connecting a microprocessor and a modem, where terminals TDI1 and RDO1 are for RS-232C, terminals TDI2 and RDO2 are for RS-422, and terminals TDI3 and RDO3 are current loops. It is for the method. In addition, although not shown here, the other side of the connector CON is connected to a modem operating in any one of an RS-232C method, an RS-422 method, and a cut-through loop method.

In addition, in FIG. 1, RTS, DTR, CTS, DCD, DSR, C / L, etc., respectively, represent control signals, which are not important components in the present invention, and thus detailed description thereof will be omitted.

Hereinafter, the operation of the multifunctional transmission control circuit having the above configuration will be described.

First, the operation when the connector CON is connected to a modem operated by the RS-232C method, that is, when the microprocessor MP and the modem transmit and receive data by the RS-232C method, will be described.

When data is transmitted in the RS-232C method, data from the transmission data output terminal TDO of the microprocessor MP is transferred from the line driver U1 of the RS-232C method transmission unit 1 and the RS of the connector CON. It is sent to the modem through the transmission data input terminal (TDI1). That is, when the connector CON is connected to a modem operated by the RS-232C method, the terminal TDI2 for the other method of the connector CON. The RDO2, TDI3, and RDO3 are not connected to the modem. The data TXD output from the transmission data output terminal TDO of (MP) is transmitted by the RS-232C method through the line driver U1 for the RS-232C method.

The received data RXD applied from the modem through the received data output terminal RDO1 is applied to the AND gate AND through the RS-232C type line receiver U3. In this case, the other line receivers U7, Since U10 is not connected to the modem, the other input terminal of the AND gate AND is brought to a high level by pull-up resistors R1 and R2. Therefore, the received data through the RS-232C type line receiver U3 is input to the received data input terminal RDI of the microprocessor MP through the AND gate AND.

Subsequently, when the connector CON is connected to the modem operated by the RS-422 method, the terminals TDI1, RDO1, TDI3, and RDO3 of the connector CON are not connected to the modem as described above. The output data TXD output from the terminal TDO of the processor MP is converted through the RS-422 type line driver U7 to be converted into the RS-42 type and transmitted to the modem. The received data input from the modem via the receive data output terminal RDO2 of the connector CON is applied to one input terminal of the AND gate AND through the RS-422 type line receiver U6. Similarly, since the other input terminal of the AND gate AND is applied with a high level (However, in the case of the line receiver U3, although not shown, in case of being disconnected from the modem by the internally provided capacitor and inverter, Outputting high level], and the received data applied from the RS-422 type line receiver U6 is applied to the received data input terminal RDI of the microprocessor MP.

Next, when the connector CON is connected to the modem operated by the current loop method, the terminals TDI1, RDO1, TDI2, and TDO2 of the connector CON are not connected to the modem, and thus the terminals of the microprocessor MP. The data TXD outputted from the TDO is transmitted to the transmission data input terminal TDI3 of the connector CON through the current loop type line driver U9, thereby being transmitted in the all-puroop type. The received data from the modem received from the receive data output terminal RDO3 of the connector CON is applied to one input terminal of the AND gate AND through the current loop type line receiver U10. Similarly, since the other input terminal of the AND gate is in the high level state, the received data applied from the line receiver U10 is input to the receiving data input terminal ROI of the microprocessor MP.

[Effects of the Invention]

As described above, according to the multi-function transmission control circuit according to the present invention, it is possible to transmit various types of data to one type of computer and to receive data from a modem operated in various ways. As a result, the inconvenience of using the computer model has to be eliminated, and the compatibility of the computer can be improved.

Claims (1)

RS-232C transmission unit 1 composed of RS-232C-type line driver U1 and line receiver U3 between connector CON and microprocessor MP to be connected to modem 1, and RS RS-422 transmission unit (2) consisting of a line driver (U7) and a line receiver (U6) for a -422 method, and a current loop method consisting of a line driver (U9) and a line receiver (U10) for a current loop method. The transmission unit 3 is provided, but the transmission data output terminal TDO of the microprocessor MP is connected to the connector (1) through the line drivers U1, U7 and U9 of the transmission units 1 to 3 according to the above methods. The transmission data input terminals TDI1-TDI3 of the corresponding method of CON are connected to each other, and the line receivers U3, U6, of the corresponding methods are connected to each of the reception data output terminals RDO1-RDO3 of the connector CON. The input terminal of the AND gate AND is connected to each other through U10, and the connection point between the line receiver U6 and the AND gate AND, and The power supply voltage Vcc is connected to the connection point of the receiver U10 and the AND gate AND through the pull-up resistors Rl and R2, respectively, and the microprocessor MP is received at the output terminal of the AND gate AND. And a data input terminal (RDI) so that the data input terminal (RDI) is connected so as to transmit or receive data of any type regardless of the type of computer.

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