Make free pc-to-pc and cheap pc-to-phone, pc-to-fax, phone-to-pc, fax-to-pc calls over Internet/VoIP or ISDN/PSTN telephone networks. Use your computer as Internet telephone, USB phone, ISDN telephone, ISDN fax, answer phone, fax software, voicemail, caller ID, CLIP/CLIR, audio conferencing, call answer, call transfer, call forwarding, call waiting, call accounting, call recording, and PBX.

Version 5.0 features unspecified improvements and bug fixes.