[Asterisk-Users] How to make/recieve call using asterisk when thereis a power failure?

[James]

>   I am supportive of the asterisk, but I have some concern, though the concern also applies to traditional pbx as well. Hope someone can shine some light into it. Thanks.
>   During a power failure situation, analog pstn lines that connect directly to the analog phones will most likely still be able to make and receive calls. 
>   However, for the Asterisk implementation, unless you have a huge ups, you will not be able to make and receive any call during power failure, since there will be no power to the Asterisk server. And since all the incoming lines, be it analog lines or T1/E1 are connected to the Asterisk, these lines wont be able to function at all.  

See google for powerfail transfer switch. Companies like Valcom make them. 
This is how you handle it on a hardware PBX. It sits in front of the pbx, 
and on powerfail switches over to an alternate output where you'd hang 
POTS phones.