The Taridium ipbx is a complete software-based VoIP PBX system that replaces a traditional proprietary hardware PBX. It runs on Linux without the need for extra software licenses, and is based on the SIP standard. It supports many phones and is available for free in a 5 user version.
Gemeinschaft is a PBX based on Asterisk, MySQL, Apache, and PHP, and designed for high availability and clustering. It provides automatic provisioning for mass deployment, and can handle over 10,000 users. Administration is done via shell scripts or a Web GUI. Hot-desking and mobility are supported. German voice prompts are included. There is a standards-compliant Web GUI with internationalization (and German and English translations). Outbound and inbound routing with full PCRE support is included.
sYnergy is a Web-based groupware and communication solution for use with an intranet. It includes email mailboxes, a fax viewer and sending function, contact lists, an appointment and task management function, a picture database, and a function for listening to voice messages. The extensive user management enables administrators to assign various permissions to each user and to exchange data e.g. contacts, appointments, or tasks. It also offers a function to import existing data.
Callweaver is a community driven software PBX project. The most important differences between Callweaver and Asterisk are built-in STUN support, the use of SpanDSP for better codecs and full T.38 fax over IP support, Sqlite instead of Berkeley DB, universal jitterbuffer, POSIX timers to avoid Zaptel timing dependencies, greater speed, more efficient dialplan execution, and greater stability.
YaaCs (Yet Another Advanced Cati system) is written in Tcl/Tk to manage and realize computer assisted telephone interviewing (CATI) and telemarketing. It make easy monitoring survey progress (giving several information), and it allows the management of the the survey with several administration tools. It simplifies the interviewer's work reading all contact's data from an easy and functional GUI. It can send faxes via hylaFAX and save all contact's data in a PostgreSQL database.
Sipcat is a software IP telephony system that helps businesses increase productivity and reduce telecommunication costs. It allows you to start running your own voice over IP PBX in a matter of minutes. It contains a complete Linux distribution, including Asterisk and all required 3rd party software.