user manual

EIA-232-D Connections

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Table B-1. EIA-232-D Interconnect Signals

Number

Signal

Mnemonic

Signal Name and Description

1 Not used.

2TxD Transmit Data. Data to be transmitted; input to modem from terminal.

3RxD Receive Data. Data which is demodulated from the receive line; output from

modem to terminal.

4RTS Request To Send. Input to modem from terminal when required to transmit a

message. With RTS off, the modem carrier remains off. When RTS is turned

on, the modem immediately turns on the carrier.

5CTS Clear To Send. Output from modem to terminal to indicate that message

transmission can begin. When a modem is used, CTS follows the off-to-on

transition of RTS after a time delay.

6DSRData Set Ready. Output from modem to terminal to indicate that the modem

is ready to send or receive data.

7SG Signal Ground. Common return line for all signals at the modem interface.

8DCDData Carrier Detect. Output from modem to terminal to indicate that a valid

carrier is being received.

9-14 Not used.

15 TxC Transmit Clock (DCE). Output from modem to terminal; clocks data from

the terminal to the modem.

16 Not used.

17 RxC Receive Clock. Output from terminal to modem; clocks input data from the

terminal to the modem.

18, 19 Not used.

20 DTR Data Terminal Ready. Input to modem from terminal; indicates that the

terminal is ready to send or receive data.

21 Not used.