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.
VoipRent is a Brussels-based company providing rental solutions to VoIP Service Providers. It was founded in November 2002 as an evolution from Mobile Services, a company that was specialized in VoIP consulting.