Asterisk is the world's leading open source PBX, telephony engine, and telephony applications toolkit. Offering flexibility unheard of in the world of proprietary communications, Asterisk empowers developers and integrators to create advanced communication solutions...for free.
Digium? the leader in open source telephony, offers Asterisk Business Edition, a professional-grade version of its acclaimed open source PBX for the Linux operating system. Asterisk Business Edition provides tested reliability of critical functions and features, tailored for small- and medium-sized business applications.