Interface SpecificationsSerial interface pin assignments

The serial interface connector pin assignments and a description of the interface signals are shown in the table below. The direction of signals is given relative to the printer.

Signal Pin

1

2

3

4

5

6

7

20

Signa I

 

Direction

Description

FG

 

 

 

 

This line is connected to the printer chassis.

 

 

 

 

TXD

 

OUT

Transmits data. This pin transmits serial data

 

 

 

 

 

from the printer to the computer.

RXD

 

IN

Received data. This pin transmits serial data from

 

 

 

 

 

the computer to the printer.

RTS

 

OUT

Request to send. This pin is held high by the

 

 

 

 

 

printer.

CTS

 

IN

Clear to send. This pin indicates that the

 

 

 

 

 

computer is ready to receive data from the

 

 

 

 

 

printer. The printer will not proceed unless the

 

 

 

 

 

signal is high. Can be set high with SelecType.

DSR

 

IN

Data set ready. This pin indicates that the

 

 

 

 

 

computer is ready to receive data from the

 

 

 

 

 

printer. Can be set high with SelecType.

 

 

 

 

 

 

SG

 

 

 

 

Signal ground. This pin provides a ground for all

 

 

 

 

 

 

 

 

 

the signal lines.

DTR

 

OUT

Data terminal ready. This pin indicates whether or

 

 

 

 

 

not the printer is ready to receive data. If the

 

 

 

 

 

printer ready protocol is not selected, this pin is

 

 

 

 

 

always high (i.e. the printer is ready to receive

 

 

 

 

 

data). If printer ready protocol is selected, the

 

 

 

 

 

printer can accept data when the pin level is high,

 

 

 

 

 

and cannot accept data when the pin level is low.

 

 

 

 

 

When the DTR signal goes low the host computer

 

 

 

 

 

must stop sending data within 128 characters.

 

 

 

 

 

Can be set high or low with SelecType.

 

 

 

 

 

 

Technical Specifications 8-17