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* Address book* Quick dial panel* Optional Automatic pop-up window for incoming call* Always on top* Call logs* Voice mail message information* Account password encryption* Upgrade notification* Adjustment of audio device* Codecs priority* Portable storage compatibility* Multilanguage supportRe-branded Zoiper:* Basic: colours, name and logo of your choice;* Re-branding with additional development: e.g. changing the language; adding, disabling, removing of menus/options/buttons; adding functionalities; * Complete: you can go for complete change of the interface and functionality.Info about Zoiper OEM can be obtained at zoiper@attractel.com Zoiper Biz, the advanced version of Zoiper Free, gives more features: * Native conferencing* API* TLS/TCP support with SIP* TLS with SRTP support* g.729 (optional)* Mail program plug-in: Outlook integration* Callto URL protocol* Automatic provisioning (XML)* Call forward* Auto answer* Incoming URL handling* Automatic opening of incoming URL* Access voice mail message with one button* Attended transfer (native)* Call recording (Single file recordings)* Command line dialing* Custom ring tones* Open URL on different call events* Call history* Call transfer* Unlimited number of accounts* Changeable number of lines (up to 6)* More!Both Zoiper editions may be customized to unique customer requirements.