Build | Fix | Re-use

APC Back-UPS RS 800 USB Mod

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


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