what is sip phone

A SIP phone is a type of phone that uses the Session Initiation Protocol (SIP) to manage multimedia communication such as voice and video calls over an internet connection. Unlike traditional phone systems that use the public switched telephone network (PSTN), SIP phones rely on internet technology to make secure and reliable calls. SIP phones can be simple software-based softphones or purpose-built hardware devices that appear much like an ordinary telephone or a cordless phone. SIP phones connect to a VoIP phone service without extra hardware or servers, making them highly flexible and scalable. The SIP protocol enables organizations to have unified communications as it integrates basic phone capabilities with video, email, instant messaging, and more. SIP also enables SIP trunking, expanding the capabilities to communicate not just between internet-connected endpoints but to any phone number, whether landline or virtual.