The battery in the ONT only powers the phone after five minutes. If you plug the Power supply from the ONT/BBU into a UPS device, this should add additional power. Sounds like in this case (the person who asked the question) the UPS is nonfunctional.
A UPS SHOULD provide power for voice and data while the battery lasts..
Written by Mike Isaksen - Jon Smirl
Last updated on 06.30.07