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.
TelecoTech has the operation to provide hosted VoIP services and is a reseller and technical support and consultant company for various brand name VoIP providers.