I never knew quite how VoIP worked until I was involved in a large Cisco VoIP rollout. I knew about the functionality that can be gained from setting up your own PBX if you know what you're doing so I decided to buy a Cisco 2801 router and teach myself how to use IOS (Cisco's OS for the router). I already had had my own Exchange server and it was always my intention to hook it up to a PBX and to get Outlook Voice Access (unified messaging) working. Unfortunately due to standards issues the technology didn't exist to hook up Exchange directly to a Cisco 2801 router until Exchange 2007 SP1 and newer version of Cisco IOS.
When I got the opportunity to throw all this hardware and software together I was able to create a fantastic setup worthy of my technoheadedness.
Below is a link to the wiring diagrams for my flat. It was a fairly ambitious undertaking and required in excess of 1km of CAT5e cable and several months of work to retrofit. I would never recommend that anyone ever try and wire up their property unless they're seriously renovating - it was a nightmare and took forever. I wanted it because I was supplying PoE for the telephony devices and my switch runs at 1Gbps otherwise it wouldn't have made sense.
Link to Flat Schematics page (all network points marked in blue).
Below is a link to a topological network diagram of my proposed VoIP/LAN solution. I have not fully completed implementing it yet - I am still waiting on a second landline (TalkTalk) and the VoIP GSM gateway. That aside, my network is up and running, and (incidentally) serving this website.
Link to Topological Network Diagram (VoIP/LAN) page. [coming soon]
Below is a link to details of my server room. It is not your average home server setup. There's a 14U cabinet with 3 rack servers, a rack mounted Cisco router and a 24-port 1Gbps PoE switch, and a 48-port patch panel. I have an air conditioning unit to cool the cupboard sufficiently - which vents into my boiler room. I have a very very warm boiler room.
Link to My Server Room page.
Below is a link to some images of a Cisco 7912G up and running with the ringtone from CTU in 24 the TV series.
Link to Telephones page.