We had some nasty weather in the Philadelphia area on Saturday and Sunday. The temperature fell from 55 to 25 degrees Fahrenheit in about four hours on Saturday evening. During that time rain changed to snow, creating a scene reminiscent of Narnia. At about 9:30am on Sunday, the power went out due to downed trees in the area. Electric service wasn't restored until almost 6:00pm, so we were without electricity for about 7.5 hours.
One of the things that Kathleen and I had wondered since we moved to Newtown was, how would our Voice over IP-based home telephone service work in emergency conditions? Up to now, we hadn't experienced a weather-related emergency. This would be our first chance to see if calls could still be made after a power failure.
Since we moved in, I installed two rather large APC Uninterruptible Power Supplies from the Small Business product category. We felt we needed one in the Home Office and one in the basement where the VoIP and DSL equipment live. The UPS in the Home Office was mainly there to keep our PCs from crashing as a result of power fluctuations. The one in the basement was intended to keep the DSL connection and the VoIP lines running in the event of a power failure.
I was pleased to find out that the APC UPS in the basement kept our DSL router, firewall, and two Motorola VoIP telephone adapters running for just over three hours before the battery was drained. During this time I made several calls to the electric utility. All of those calls were connected properly. There were no call quality issues whatsoever. Kudos to our DSL and VoIP provider, Speakeasy for engineering their network so that a local power failure didn't interrupt our DSL and VoIP service. I know they use Covad for their local network services and Level 3 for VoIP network engineering. Both of these providers' local gear kept running during our power failure.
Most power failures that we experience around here are pretty short and have to do with things like automobile accidents that take down utility poles. All we're trying to do with our UPS equipment is survive this sort of brief outage, in case someone calls in to us on one of our VoIP numbers. Kathleen and I have mobile phones that we can use to make outgoing calls and that will probably keep working during extended outages like the one we experienced yesterday.
Now that we've experienced a day-long power failure, I definitely recommend that people who are replacing their old-style telephone service with VoIP invest in a UPS that has the capacity to power their terminal equipment (including their router, firewall, and TAs) for at least three hours. I would segregate these devices onto their own UPS even if you have other devices that you want to protect. This will simplify your planning because you will not have to arrange for the shutdown of non-essential electronic equipment in order to maximize the runtime of the UPS that supports your VoIP phones.
Your VoIP phones may not survive every outage with this safety margin, but they'll keep running during many of the power failures that we experience in the Continental United States.