How to Wire a 9-Pin Serial Port Cable

Construct your own serial cable using DB9 connectors.

Serial port connections are widely supported and in many cases required to configure electronic equipment such as network routers and switches, Point of Sale equipment, electronic weight scales, and some computer-to-computer connections. The 9-pin serial port is a standard hardware feature on most PC-based computer systems. Serial port cables can be purchased or you can employ your soldering skills to quickly construct your own 9-pin serial cable that supports most equipment "pinout" requirements.

Things You'll Need

• 10 foot data cable with nine 24 AWG
• Soldering iron and solder
• Wire stripping tool
• Phillips screwdriver
• Two 9-pin D connector covers
• Two 9-pin D female connectors

Instructions

1. Strip three inches of the plastic jacket from the ends of the data cable. Remove a 1/2-inch length of the plastic jacket from the end of each wire inside the data cable. Twist the ends of each individual wire.

2. Plug in the soldering iron and allow it to heat up. Identify the pin numbers on the back of each 9-pin connector; look for the small numbers beside each pin. Place the black wire on pin 5 of the first 9-pin connector, and then solder to secure the wire. Place the opposite end of the black wire on pin 5 of the second 9-pin connector, and then solder to secure the connector.

3. Place the red wire on pin 2 of the first 9-pin connector, and then solder to secure the wire. Place the opposite end of the red wire on pin 3 of the second 9-pin connector, and then solder to secure the connector.

4. Place the yellow wire on pin 3 of the first 9-pin connector, and then solder to secure the wire. Place the opposite end of the yellow wire on pin 2 of the second 9-pin connector, and then solder to secure the connector.

5. Remove the screws on the connector covers and then disassemble each connector cover. Place the covers on the 9-pin connectors and press the covers into position. Replace and tighten the cover screws.

References

• Lammert Bies:RS232 Serial Cable Pinout
• Windmill Software:Serial Port and RS232 Connections