Interface Specifications

 

Pin assignments for the serial interface

 

Pin

 

 

 

 

 

 

Signal

 

Direction

Description

 

1

C h a s s i s

G N D

-

 

This is connected to the printer chassis.

 

 

 

 

 

 

 

 

2

TXD

 

OUT

Transmits data for X-ON/X-OFF.

 

 

 

 

 

 

 

3

RXD

 

IN

Received data. This pin transmits serial

 

 

 

 

 

 

data from the computer to the printer.

 

 

 

 

 

 

 

 

7

Signal

GND

-

 

Signal (logic) ground level.

 

 

 

 

 

 

 

11

REV

 

OUT

Same as DTR.

 

 

 

 

 

 

(= 2nd RTS)

 

 

 

 

 

 

 

20

DTR

 

OUT

Data terminal ready. This pin indicates

 

 

 

 

 

 

whether the printer is ready to receive

 

 

 

 

 

 

data. If the printer ready protocol is not

 

 

 

 

 

 

selected, this pin is always HIGH (that

 

 

 

 

 

 

is, the printer is ready to receive data). If

 

 

 

 

 

 

the printer ready protocol is selected,

 

 

 

 

 

 

the printer can accept data when the pin

 

 

 

 

 

 

level is LOW. When the DTR signal

 

 

 

 

 

 

goes LOW, the host computer must stop

 

 

 

 

 

 

sending data within 128 characters, The

 

 

 

 

 

 

DTR signal can be set HIGH or LOW

 

 

 

 

 

 

with SelecType.

 

 

 

 

 

 

 

Note: The column heading “Direction” refers to the direction of signal flow as viewed from the printer.

Technical Specifications 7-25