Yep, was hoping someone had some experience before I went poking around inside it!Take a look at the printed circuit board. It's a single rail so shouldn't be too difficult to work out?
I opened it up and had a look see, you are right..DO NOT POWER ON the unit while examining the circuit board. You are merely going to observe the copper traces and try to determine what pins are outputs(ground or voltage). The traces should be large and should be connected to a plurality of pins. They should also be connected to a leg of a large transistor(or other output device) which will surely be attached to a substantial sized heat sink.
When you have mapped these pins and determined their physical position within the connector body, re-assemble the unit and using a multi-meter, probe the pins 'carefully' to find which ones are ground and which are voltage. Be aware that most telecom equipment operates on a NEGATIVE 48 volt power supply.
by Jake Hertz
by Aaron Carman
by Jake Hertz