Motorola MVME197LE User Manual
Page 70
EIA-232-D Interconnections
A-2
User’s Manual
A
Table A-1. EIA-232-D Interconnections
Pin
Number
Signal
Mnemonic
Signal Name and Description
1
---
Not used.
2
TXD
TRANSMIT DATA - data to be transmitted is furnished on
this line to the modem from the terminal.
3
RCD
RECEIVE DATA - data which is demodulated from the
receive line is presented to the terminal by the modem.
4
RTS
REQUEST TO SEND - RTS is supplied by the terminal to the
modem 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.
5
CTS
CLEAR TO SEND - CTS is a function supplied to the
terminal by the modem which indicates that it is permissible
to begin transmission of a message. When using a modem,
CTS follows the off-to-on transition of RTS after a time
delay.
6
DSR
DATA SET READY - data set ready is a function supplied
by the modem to the terminal to indicate that the modem is
ready to transmit data.
7
SIG-GND
SIGNAL GROUND - common return line for all signals at
the modem interface.
8
DCD
DATA CARRIER DETECT - sent by the modem to the
terminal to indicate that a valid carrier is being received.
9-14
---
Not used.
15
TXC
TRANSMIT CLOCK - this line clocks output data to the
modem from the terminal.
16
---
Not used.
17
RXC
RECEIVE CLOCK - this line clocks input data from a
terminal to a modem.
18,19
---
Not used.
20
DTR
DATA TERMINAL READY - a signal from the terminal to
the modem indicating that the terminal is ready to send or
receive data.
21
---
Not used.