I bought an “APC Back-UPS ES 550” awhile back from CostCo without knowing for sure if it would work with the Seagate BlackArmor NAS. It works great so far. I was afraid I would have to hack on the configuration file for the software but it worked out of the box without any extra effort other than enabling the UPS Manager.
I had a second dilemma which was that I use the NAS as my print server for an older “Brother MFC 7420” printer and did not want to loose that configuration. There is only one USB port off the back of the unit that is supposed to work with printers and UPS. So for my next surprise, I found that it works for both the UPS and printer with an old un-powered notebook USB hub that I got as a door prize at some Cisco event.
I may test plugging up my old 500GB Seagate USB hard disk to that hub as well and see if it recognizes the space and makes it available.
So for anyone else, I cannot vouch for all UPS and printers but my configuration above is working great.