This is a full featured and very small IAX based software phone for Microsoft Windows platforms (only). The application is distributed as a freeware for personal use. Click here to see the online help for a complete description of the application. Some of the main features are:

registering with Asterisk PBX;
supporting IAX2 protocol (only);
can act as a remote PSTN/GSM/PCS/CDMA gateway for any Asterisk server;
multiple audio codecs support (with auto-negotiation): aLaw, uLaw, GSM, iLBC, Speex;
can register with multiple servers (max. 8);
independent audio codec configuration for each registration server;
fully support for the ATCOM AU-100 USB phone (http://www.atcom.com.cn/engweb/bUSBPhone.html);
fully support for the Yealink USB phone (http://shop.voismart.it/products.php?cat=12);
fully support for the Eutectics Inc. USB phones (http://www.eutecticsinc.com/products/products.html);
web browser integration (start app and/or dial using a link like diax://number/alias);
configurable audio latency;