The TekPhone is a SIP VoIP softphone runs under windows (2003 Server, XP, Vista). It provides UA agent functions based on RFC 3261. The software only supports RFC 2833 for DTMF digit delivery and G.711 A - Mu law codecs and UPnP for NAT traversal. It also allows you to manually set external IP address. With TekPhone you can specify your own welcome message. It can record incoming audio if away mode selected.
No matters that you are a college student, a business professional, a merchant or a retailer, this software will not disappoint you at any point.
The new version 1.4 let you select audio input.