Useful Stuff and Fings...

Xvision CCTV Client for Windows for use with Xvision XHD DVRs

3 pole COBO

Pin-Out for 3 pin tractor type auxiliary plugs and sockets, also know as COBO or DIN-9680

Pin 15/30 is permanent +12v, Pin 31 is Ground, Pin 82 is +12v when engine running

UK 7 Pin Trailer Plug and Socket wiring Diagram in PDF

"Sixty on Thirds" Change Bell Ringing Chart