Pin Number - Compuprint 4056 Programmer's Manual

The following table lists the RS-422/A serial interface signals::
ISO Circuit ID Signal Source
T (A)
T (B)
R (A)
R (B)
G
SHIELD

Pin Number

Printer
Host
C-17
13 Transmit.
MARK signal is present when
printer is not sending data.
14 Transmit Return.
16 Receive.
A MARK level is expected when
sender is in idle state.
19 Receive Return.
7 Signal Ground.
Always connected to the 0 Volt of
the power supply.
1 Cable Shield.
Optionally connected to the frame
ground of the printer via a suitable
jumper.
Description