I’ve played with Asterisk over the years, and it’s somewhat to write home about (you know the phone system-like snapin to any Unix or Linux operating systems?)
One of the things that caught my attention from almost the early days was it’s “support” for some proprietary IP phone drivers and protocols. Particularly Cisco’s SCCP and Nortel’s UniSTIM. Session Initiation Protocol or SIP is an “open” standard, meaning that the way the phone communicates to the phone system (that’s now a server) is supposed to use a uniform specifications outlined in Request for Comment in the Holy Grail of Internet Standards. That RFC is rather interesting, because while these phones could work on any system that supports SIP, basically, it’s almost like having a house phone with an IP stack instead.
I have focused on SIP in other posts, and I don’t really support this idea on phones, because it’s almost like having a landline just that it communicates over the Internet. I personally feel that SIP is way too religious in the way a vendor must follow. In fact, there is a movement to obsolete that with WebRTC. With that aside, SIP is going to be withheld for the rest of this story.