We have an installation that just switched all their lines to VOIP, they did not tell us about it and normally the panels self test every day. One day the VOIP system went down and we stopped getting test signals from the 10 buildings on site, later we found out it was due to the system shutting down and not being reset. They corrected this and now we are getting test signals. We are used to using Analog phone lines where we can set up line siezure using an RJ31X block. We contacted the State Fire Marshal and we were told VOIP was ok as long as it met the rest of the codes. The issue I see is they do not have a 24 hour battery backup UPS on their VOIP system to avoid the kind of problem that occured. Analog lines would not go down if there was a power outage. Can you help me with a code reference to support this UPS backup?