Asterisk is the beginning of the end of proprietary and legacy phone systems. Period.
Backed by Digium, Asterisk is one of the few opensource telephony solutions that can produce what it claims; a solid telephony solution for a fraction of the price of any phone system on the market. Asterisk takes that promise a little further and provides a malleable solution; Asterisk can be nearly anything telephony. Want to add a new voicemail solution to your existing telephony system? Need a small PBX in your home office? How about an completely customizable VoIP solution that can integrate multiple phone manufactures and facilitate intelligent communication between all sites in your enterprise?
Asterisk is your answer.
Although I am a Digium Certified Asterisk Professional (dCAP), I have only begun to scratch the surface of what Asterisk can accomplish in the professional enterprise. I hope you find the information I have compiled on Asterisk helpful.