Several years ago I bought a 2.4KVA UPS for the bargainous price of £90, and it’s still working nicely. It’s kept my computer running for about an hour in the past, and I’m glad I have it since power cuts used to be quite frequent around here.
Now I’m looking to get it hooked up to a computer so that it’s status can be monitored and systems can be safely shutdown if I’m not around. UPS serial connections don’t quite use standard RS232 pinouts and communications – it’s kind of a hybrid between RS232 and a more basic status-line implementation. The cables that connect UPSes to their monitoring machines generally require special wiring. In the case of the Compaq T2400h, this is what’s required (taken from a post by the guy who was the source of my UPS):
Male -> Female
1 -> 3
2 -> 2
4 -> 5
6 -> 7
and 4 <-> 6 on the female side are linked
Note that this pinout is unconfirmed, but I will be attempting to make one of these cables to test it, and hopefuly get it working with NUT.
Update: I found some information on using a T2400h with NUT, which includes a confirmation of the wiring of the serial cable.