What is an SIP Phone?

An SIP phone is a telephone that uses the SIP (Session Initiation Protocol) standard to make a voice call over the Internet, or VoIP. The SIP phones come with several value added services like voicemail, e-mail, call number blocking etc. There are (normally) no charges for making calls from one SIP phone to another, and negligible charges for routing the call from a SIP phone to a PSTN, or public switched telephone network phone.

To use SIPphones you need either a SIPphone adapter or soft phone software and a broadband internet connection. To make free in-network (SIP to SIP) calls, both sides of the call must have a SIPphone adapter or soft phone.

There are two types of SIP Phones. The first type is the hardware SIP phone, which resembles the common telephone but can receive and mak/e calls using the internet instead of the traditional PSTN system. SIP Phones can also be 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.