SIP Phones are also called VoIP Phones or Softphones. These are telephones that use VoIP technologies for making calls over both an IP Network or the traditional PSTN networks.
There are two types of SIP Phones. The first type is the hardware SIP phone. It resembles the typical telephone, but uses purpose-built hardware to receive and makes calls using the Internet, instead of the traditional PSTN system. The second type is software-based. These allow any computer to be used as a telephone by means of a headset with a microphone and/or a sound card. A broadband connection and connection to a VoIP provider or a SIP Server are also required. Software SIP Phones can also run on mobile devices such as Android and iOS.