user manual

EIA-232-D Interconnections
A-2
A
Table A-1. EIA-232-D Interconnections
Pin
Number
Signal
Mnemonic Signal Name and Description
01 Not used.
02 TxD TRANSMIT DATA. Data to be transmitted; input to the modem
from the terminal.
03 RxD RECEIVE DATA. Data which is demodulated from the receive
line; output from the modem to the terminal.
04 RTS REQUEST TO SEND. Input to the modem from the 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.
05 CTS CLEAR TO SEND. Output from the modem to the 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.
06 DSR DATA SET READY. Output from the modem to the terminal to
indicate that the modem is ready to transmit data.
07 SIG-GND SIGNAL GROUND. Common return line for all signals at the
modem interface.
08 DCD DATA CARRIER DETECT. Output from the modem to the
terminal to indicate that a valid carrier is being received.
09-14 Not used.
15 TxC TRANSMIT CLOCK (DCE). Output from the modem to the
terminal; clocks data from the terminal to the modem.
16 Not used.
17 RxC RECEIVE CLOCK. Output from the modem to the terminal;
clocks data from the modem to the terminal.
18, 19 Not used.
20 DTR DATA TERMINAL READY. Input to the modem from the
terminal; indicates that the terminal is ready to send or receive
data.
21 Not used.