AXVoice SIP International Home service so I get unlimited voice to the US and 40+ countries and when one phone is busy, I can just pick up another and dial. It comes out to about $18 / month.
The PBX is currently running on an Intel Atom mini ITX board (a D945GCLF2) running a headless version of FreePBX / Asterisk / Centos. (I think you could get this configuration running on just about any old PC you have laying around. I first brought it up on an old Dell tower.)
Technical How To and Asterisk: the Definitive Guide, I got a "raw" Asterisk instance running on Ubuntu 12.10. This doesn't have all the bells and whistles of the Centos version, but it did give me a look at configuring Asterisk using it's own configuration files. I brought up a simple 2 extension PBX connected to AXVoice just to demonstrate that it works. It took a couple of hours, some digging in the Asterisk book and Google - and two config files. In addition to being a great Asterisk technical reference, the book has some great background on telephony.
|RPi CID on a tiny 3" screen|
I'm still using my CID decoder running on the Raspberry Pi to produce a web page with the Caller ID, but I'm thinking I'll move this function to the PBX - where it belongs - and reuse the RPi for something else!
The idea behind this project was to A.) learn something about Asterisk; B.) get unlimited calling; C.) have some fun - and all of these objectives were met! If you're at all interested in learning about telephony (or a home PBX) I'd highly recommend the exercise!