A

EIA-232-D Interconnections

Table A-1. EIA-232-D Interconnections

Pin

Signal

Signal Name and Description

Number

Mnemonic

 

 

 

 

 

 

 

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.

 

 

 

A-2

User’s Manual

Page 70
Image 70
Motorola MVME197LE Table A-1. EIA-232-D Interconnections, Pin Signal Signal Name and Description Number Mnemonic