Charlestown landlines use Voice over Internet ProtocolVoIP services convert your voice into a digital signal that travels over the Internet. If you are calling a regular phone number, the signal is converted to a regular telephone signal before it reaches the destination. VoIP can allow you to make a call directly from a computer, a special VoIP phone,... READ MORE (VoIP) to manage their calls. A VoIP system converts analog voice signals into digital signals over your wi-fi connection. A VoIP server is used to connect calls to other telephone networks. International calls are free. See Voice over Internet Protocol definition.