I got hold of a used APC Back-UPS RS 800 but unfortunately did not get the data cable which gets supplied with the unit when purchased new so i decided to make my own. The problem with these units is that the data port at the back uses a RJ50 instead of a RJ45 connector and these cables are kinda hard to come by. The difference between the two is that the RJ50 uses 10 wires and the RJ45 uses 8 and most computer stores only seem to stock the RJ45 type connector or cables, so i decided to hardwire a USB cable directly to the circuit board of the UPS.

Here is an example of a RJ45 and a RJ50 connector:

To get started i needed a USB cable which i removed from an old mouse i had laying around.

After stripping the wires solder them to the circuit board:

• Copper wire – to chassis ground
• Red Wire – to Pin 1
• Black Wire – to Pin 7
• White Wire – to Pin 9
• Green Wire – to Pin 10