All Points uses Voice over the Internet Protocol (VoIP) to transmit audio over broadband internet. Unlike traditional phone lines that rely on copper wires, VoIP transmits signals digitally for crystal-clear quality. If you are using VoIP services, it is recommended that you purchase a battery back-up for your router. VoIP service is dependent on power and an internet connection. If either of these services is disrupted, you will be unable to make calls without a back-up battery installed.