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A softphone is a software program for making telephone calls over the Internet using a general purpose computer, rather than using dedicated hardware. Often a softphone is designed to behave like a traditional telephone, sometimes appearing as an image of a phone, with a display panel and buttons with which the user can interact. A softphone is usually used with a headset connected to the sound card of the PC, or with a USB phone.[1]


Currently, softphones are widely being used by the businesses, especially the call centers. It fits well for the long distance calling that is based on Internet (or Voice over IP) as both of them are hardware-independent services. This allows a number or features, such as- virtual number, Customer relationship management integrations, etc. to be availed for the users. Softphone are even easier to be monitored and recorded with dialers, which serves the quality purpose of call center well. [2]

Communication protocols[edit]

To communicate, both end-points must support the same Voice-over-IP protocol, and at least one common audio codec.

Many service providers use the Session Initiation Protocol (SIP) standardized by the Internet Engineering Task Force (IETF). Skype, a popular service, uses proprietary protocols, and Google Talk leverages the Extensible Messaging and Presence Protocol (XMPP).

Some softphones also support the Inter-Asterisk eXchange protocol (IAX), a protocol supported by the open-source software application Asterisk.


A typical softphone has all standard telephony features (DND, Mute, DTMF, Flash, Hold, Transfer etc.) and often additional features typical for online messaging, such as user presence indication, video, wide-band audio. Softphones provide a variety of audio codecs, a typical minimum set is G.711 and G.729.


To make voice calls via the Internet, a user typically requires the following:

See also[edit]