I don't remember the model UPS I have (I'm at work right now), but I used to have my coax cable running through the UPS. I started having connection issues to to point I'd completely lose the Internet altogether. I unplugged the cable and put it straight into my modem - problem solved.
The cable guy also said it's not a good idea to run your cable Internet feed through the UPS...maybe it's just APC units, don't know. In either case, I'm not sure what the benefit really was anyway.