PC Cable Pinouts

IBM PC/XT, PC/AT, and Compatible Computers

The following diagrams show the serial cable pinouts for IBM PC/XT, PC/AT, and compatible computers.

»Note: Not all serial cables are configured as shown and may require an additional null-modem adapter. Check with your cable vendor for compatibility.

To Printer

 

 

To CPU XT

9-Pin

 

 

 

 

25-Pin

 

 

 

 

 

 

Female

 

 

 

 

 

 

 

 

 

1

 

Not

 

 

 

 

 

 

Used

 

 

 

RXD

2

 

 

2

RXD

TXD

3

 

 

3

TXD

DTR

4

 

 

20

DTR

DSR

6

 

 

6

DSR

GND

5

 

 

 

7

GND

 

 

 

RTS

7

 

 

4

RTS

CTS

8

 

 

5

CTS

 

9

 

Not

 

 

 

 

 

 

Used

 

 

 

 

 

 

 

 

 

 

To Printer

 

 

To CPU AT

9-Pin

 

 

 

 

9-Pin

 

 

 

 

 

 

Female

 

 

 

 

 

 

 

 

 

1

 

Not

 

 

 

 

 

 

Used

 

 

 

RXD

2

 

 

2

RXD

TXD

3

 

 

3

TXD

DTR

4

 

 

4

DTR

DSR

6

 

 

6

DSR

GND

5

 

 

 

5

GND

 

 

 

RTS

7

 

 

7

RTS

CTS

8

 

 

8

CTS

 

9

 

Not

 

 

 

 

 

 

Used

 

 

 

 

 

 

 

 

 

 

»Note: To download printer system software via the serial port, your hardware must have RTS and CTS support. Make sure that pins 4 and 5 on the 25-pin serial cable and pins 7 and 8 on the 9-pin serial cable are criss-crossed as shown in this diagram.

Technical Specifications

B-15