Zoiper Free is a IAX and SIP softphone compatible with the Asterisk platform as any other SIP or IAX capable system. Zoiper Free Edition features include: * SIP + IAX/IAX 2 protocols * STUN support * STUN server per account * T.38 fax support * Echo cancellation * DTMF tones sending * DSCP support * Support for multiple audio devices * Automatic user registration * Call transfer * Hold function * Codecs: GSM, ulaw, alaw, speex, ilbc * Adaptive Jitter Buffer * Call history *...