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 support

Re-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.