Asterisk 17

It's not really amazing. It's the OpenWRT of phone systems. There are lots of commercial PABX systems out there that are Asterisk with a skin. VOIP providers often use if for instance.

It's "dial plan", which I guess was originally a list of phone number patterns mapping to instructions one how to handle them, grew into a fully fledged but absolutely horrid language, complete with function calls, variables, and macros and threads of execution. The addition of IAX, which is effectively a protocol that lets a dial plan running in one copy of Asterisk invoke functions in another dial plan running in another copy let you build distributed PABX's.

From a computer science language design perspective the this conglomerate of organically added features is truly ghastly. But that doesn't matter. What matters is it does allow you to build amazingly complex that can deliver any feature you care to name. I've built systems that with over 20 instances of Asterisk, most with no external SIP lines of their own, that to the users functions like a single PABX in the cloud. All the calls are logged to a central place so the organisation can track who is doing what. None of this requires stepping outside of Asterisk provides in the box.

When you have a system that powerful and flexible, and yet bloody horrible to configure, it's not surprising lots of 3rd parties base their own products on it. I have absolutely no doubt those 3rd parties would not let Asterisk die. They must know, understand and appreciate the power of the open source model, so if the current project died some of them would stand up and fork a replacement.

Is anyone running it at home? What is your setup like?