ZOIPER Free IAX / IAX2 and SIP softphone.

ZOIPER 2.0 Free SIP and IAX is a user-friendly softphone, compatible with Asterisk or any other SIP or IAX capable system. High-quality VoIP experience with features like: SIP + IAX protocols, T.38 fax support, STUN support, Echo cancellation, DTMF tones, Adaptive jitter buffer, Call transfer, Hold function, Multilanguage support, Portable storage compatibility, Codecs: GSM, ulaw, alaw, speex, ilbc.

On April 10, 2009 updated, download size 2868Kb, for Windows 2000, XP, Vista, Mac OS, Linux.