How to Make a 9-Pin Serial to Ethernet Cable

Picture of How to Make a 9-Pin Serial to Ethernet Cable
These instructions will show you how to make a 9-pin serial to Ethernet cable. Serial cables are used to control and configure devices with serial ports. When converting one end to Ethernet, the signal is able to travel farther. When devices are spread out over a large area or placed inconveniently, such as ceiling-mounted projectors, being able to control multiple devices from one spot saves time and money. Only patience is required to make these cables; no prior knowledge necessary. It will take around an hour to complete a cable. After a few practice cables, they can be made in 10 to 15 minutes. With the ability to control devices from a stationary spot, you don't have to worry about searching for a remote or physically pushing buttons on the device.

Required Parts and Tools

Digital Multimeter
Wire Crimpers (Optional)
1 - RJ-45 connector (Optional)
Wire Strippers
Electrical Tape
[1]9-Pin Serial Cable
[1]Ethernet Cable
[2]4-Wire Splice Connectors
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Step 1: Strip the Serial Cable

Picture of Strip the Serial Cable
1) Cut the serial cable using the wire strippers, leaving a couple feet on the female end.

2) Using the strippers, remove roughly 2 inches of the cable covering on the cut end to expose the inner wires.

Step 2: Map the 9 Pin Holes to Inner Cables Using Multimeter

Picture of Map the 9 Pin Holes to Inner Cables Using Multimeter
1) Set multimeter to smallest Ohms setting (symbol looks like horseshoe).

2) Insert either multimeter rod (red or black) into first pin hole of serial cable.

3) Make contact with inner wires (inside inner shield) with other rod one at a time.

4) When the multimeter picks up a reading, then the pin hole being used is connected to the wire being touched.

5) Repeat steps 2-4 until all inner wires are mapped to their pin holes.

Step 3: Remove Unnecessary Inner Wires

Picture of Remove Unnecessary Inner Wires
1) Look in the device manual or online to find which pins are designated for the following:
a) Transmit
b) Receive
c) Ground (there may be multiple, pick only one)

2) Set aside the inner wires corresponding to the designated pins along with the bare wire (also ground).

3) Cut off the unnecessary inner wires.