Trixbox is now at version 2.8, but you can get some of the terminology from the video which is useful. The current version is available from http://fonality.com/trixbox/
. This is a computer based phone system aka pbx and or a voip system. I will have a follow up instructable with more details. To my knowledge, I have no financial ties with this company.
Trixbox 2.8 install in espanol: http://www.youtube.com/watch?v=mLeFp91eUE4
A second instructible is coming about Trixbox. (in progress).