Asterisk is the world's leading open-source PBX, telephony engine, and telephony applications toolkit with immense flexibility. 'Asterisk Gateway Interface 1.4 and 1.6 Programming' book by 'Nir Simionovich' will give you a firm understanding of Asterisk Gateway Interface (AGI) development and proper AGI development practices.

Building your own corporate phone system using the Asterisk open source telephony suite could result in massive cost savings for your company, but it's not for the faint-hearted: Asterisk is a complex system, and if you mess up the phone system it could end up costing you your job.

Asterisk, a PBX, telephony engine, and telephony applications toolkit, is one of open source best-kept secrets. As with many open source projects, there is a company that has been set up to provide support, Digium.

Some critics say Asterisk — the open source IP PBX — is for hackers rather than real telephony customers. EUS Networks begs to differ. The New York-based solutions provider, which works closely with Digium, has launched an Asterisk-based IP telephony solution for a hedge fund client’s trading room floors. Here’s the scoop.

Programming the Asterisk open source PBX via the Asterisk Gateway Interface (AGI) is a fun but exasperating exercise for the telephony programmer.

Sure, true fanatics are familiar with Asterisk — the open source IP telephony platform. But there are some clear signs that Asterisk is pushing beyond the open source crowd and gaining momentum within small and midsize businesses.

Voice Internet Protocol (VoIP) Telephony refers to the technology used for making telephone calls over the Internet. The two major technologies used to implement VoIP telephony are Asterisk and OpenSER. This article by Flavio E. Goncalves compares Asterisk and OpenSER topic by topic and shows the differences between them.

Asterisk is one of the best telephony solutions which is free to use. There are others such as yate that provide same type of solutions and even more custom ones. Due to the easy of implementation Asterisk has become more popular than anything else. Asterisk is very easy to use and lots of open source and closed source panels provide a GUI for it.

Sangoma produces telephony cards and writes drivers that work with open source applications such as Asterisk, Yate, FreeSwitch, and CallWeaver. Sangoma CEO and founder David Mandelstam says that before Sangoma started producing cards to work with Asterisk, the open source project was "kind of a toy for hobbyists."