Right, pull the other one. Phone systems get cheaper by the day and everyone is routing calls via the internet. Once it is setup, everything is gravy afterward other than setting new users up in the system and this can be automated.
Nope. Sorry. Not for the “secure” phone systems used by prisons, at least those that contracted with the place I worked. They used an internal VOIP PBX, sure, but there was a huge database system tied to it and a bunch of processing logic. We had probably 15-20 different servers/server groups at least involved in processing every call.