Appendix B Host Computer Interface

3. Serial Interface (Option)

3.1 RS-232C Interface

The pins of the printer’s RS-232C interface connector carry the signals listed in the table below. The table also indicates whether each signal is incoming or outgoing with respect to the printer.

Pin

In/out

Signal

Description

 

 

 

 

1

-

FG

Frame ground

 

 

 

 

2

Out

TXD

Transmit Data

 

 

 

 

3

In

RXD

Receive Data

 

 

 

 

4

Out

RTS

Request To Send

 

 

 

 

5

In

CTS

Clear To Send

 

 

 

 

6

In

DSR

Data Set Ready

 

 

 

 

7

-

SG

Signal Ground

 

 

 

 

20

Out

DTR

Data Terminal Ready

Table B-3

Brief descriptions of the signals follow.

FG - Frame Ground - (Pin 1)

This pin is connected directly to the printer frame.

TXD - Transmit Data - (Pin 2)

This output carries asynchronous data sent by the printer to the computer. It is used mainly in handshaking protocols.

RXD - Receive Data - (Pin 3)

This input carries serial asynchronous data sent by the computer to the printer.

RTS - Request To Send - (Pin 4)

This output is always held high (above 3 volts).

CTS - Clear To Send - (Pin 5)DSR - Data Set Ready - (Pin 6)

Unused.

SG - Signal Ground - (Pin 7)

All signals can transmit between the printer and the host computer to send each signal with a signal ground.

DTR - Data Terminal Ready - (Pin 20)

This output is used as a buffer nearly-full handshake line. It is held high (above 3 volts) when the buffer can accept more data.

RS-232C Interface Voltage Levels

The voltage levels of the interface signals conform to EIA RS- 232C specifications. SPACE is from 3 volts to 15 volts. MARK is from –3 volts to –15 volts. Voltages between –3 volts and 3 volts are undefined.

4. RS-232C Protocol

A protocol is a set of rules the computer follows in sending data to the printer. They are indicated on the status page. Parameters can be changed from the operator panel. See Changing Serial Interface Modes on page 3-19. The parameters and their identification codes are given below.

H1: Baud rate
Parameter valueBaud rate

 

 

12

1200

 

 

24

2400

 

 

48

4800

 

 

96

9600

 

 

19

19200

 

 

38

38400

 

 

57

57600

 

 

11

115200

Table B-4

The factory default setting is 9600 baud.

H2: Data bits

7 or 8; the factory default setting is 8.

H3: Stop bits

1 or 2; the factory default setting is 1.

H4: Parity

Parameter value

Meaning

 

 

0

None

 

 

1

Odd

 

 

2

Even

 

 

3

Ignore

Table B-5

The factory default setting is None (0 on the status printout).

B-3