UPS Hack

The UPS in object is a TRUST 750 VA (360W) model PW-4075T.

This hack started just for adding a fan blower. The article I wrote said:

My economical UPS dies every two years. Yep, the battery has to be changed but I noticed signs of overheating.
Adding a fan blower may help just a little bit. I removed two plugs and the telephone-surge-protection, opened a hole, and mounted a 60×60 fan blower.
Wiring is shown in photo, only one transistor and one 4k7 resistor to turn on the fan blower with the ups.

But then I saw a predisposition for serial port… some checks and it worked!

(todo)