Motorola MVME177 Installation And Use Manual page 78

EIA-232-D Interconnections
A
A-6
Figure A-2 shows a way of wiring an EIA-232-D connector to enable
a computer to connect to a basic terminal with only three lines. This
is feasible because most terminals have a DTR signal that is ON,
and which can be used to pull up the CTS, DCD, and DSR signals.
Two of these connectors wired back-to-back can be used. In this
implementation, however, diagnostic messages that might
otherwise be generated do not occur because all the handshaking is
bypassed. In addition, the TX and RX lines may have to be crossed
since TX from a terminal is outgoing but the TX line on a modem is
an incoming signal.
EIA-232-D CONNECTOR
GND 1
TxD 2
RxD 3
RTS 4
CTS 5
DSR 6
GND 7
DCD 8
DTR 20
Figure A-2. Minimum EIA-232-D Connection