When you receive an incoming call to your phone number, your other telephones (cell, home phone, car phone) will ring as well and the first one answered will be connected to the caller. Basically the call will be routed to all phone sets, which you will list in simultaneous ring option.
VoIPCall is a Minneapolis based Internet Telephony Service Provider [ITSP] that provides a first class Voice Over IP calling service designed for business customers, Telcos, ISPs and government entities around the world.