Softphone

From TechnologicalWiki

In computing, 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.

[edit] Applications

A typical application of a softphone is to make calls via an Internet telephony service provider to other softphones or to telephones. Service providers may offer PC-to-PC calls for free; PC-to-phone and phone-to-PC calls are possible too, in most of the cases, but usually they are't free.

Another type of softphone connects to a private branch exchange (PBX) through a local area network (LAN) and is used to control and dial through an existing hardware phone. This is often used in a call center environment to make calls from a central customer directory, and to "pop-up" information on the screen about which customer is calling, instantly providing the operator with details of the relationship between the caller and the company using the call center.

To communicate, both end-points must have the same communication protocol and at least one common audio codec.The most extended protocol is SIP(Session Initiation Protocol) by IETF.

A typical softphone has all standard telephony features (DND, Mute, DTMF, Flash, Hold, Transfer etc) and other new ones like Presence, Video, Wideband Audio and more. The minimum codecs set is G.711, GSM and iLBC. Softphone although vendors may offer more codecs and different feature set.

[edit] Requirements

To make voice calls over Internet, you should have

Any modern PC with a microphone and a speaker, or with a headset, or with USBphone.
Reliable Internet connectivity like DSL, WiFi, cable or LAN. 28.8 dial-up modem
Account with an Internet telephony service provider.