Voice over Internet Protocol (VoIP)

Voice over Internet Protocol, also called VoIP, IP Telephony, Internet telephony, Broadband telephony, Broadband Phone and Voice over Broadband is the routing of voice conversations over the Internet or through any other IP-based network.

VoIP to VoIP phone calls are sometimes free, while VoIP to PSTN (public switched telephone network) may have a cost that's borne by the VoIP user. There are two types of PSTN to VoIP services: DID (Direct Inward Dialing) and access numbers. DID will connect the caller directly to the VoIP user while access numbers require the caller to input the extension number of the VoIP user. Access numbers are usually charged as a local call to the caller and free to the VoIP user while DID usually has a monthly fee. There are also DIDs that are free to the VoIP user but chargeable to the caller.