A telephone that converts voice into IP packets and vice versa for voice over IP (VoIP) telephone service. The term usually refers to a telephone with built-in IP signaling protocols such as H.323 or SIP that is used in conjunction with an IP PBX in an enterprise. However, it may also refer to a software-based phone (softphone) that is installed in the user's PC and requires that calls be made from the PC. See softphone, VoIP, hosted VoIP and IP telephony.