I cut the four wires and if green and brown are connected the lamp on the back indicates pulses being picked up. Thought that black and red then would be an ordinary analog 2 leader pulse input but it does not seem so. Anyone that can contribute with more enlightning thoughts?
Can you tell me the order of the colours in the 4 pin plug?
If have the plastic locking tab of the plug facing down so that the gold contacts are facing upward towards you, this would be a good order for me.
The reason i say this is because the optismart unit and the Mini Sensor transmitter, as far as i can tell use the same PCB inside with just a couple of small changes to what components are fitted and the software is different. I don't have an optismart to look at but i can probably work out what wire is doing what if i know the correct order of the colours. Based on my knowledge of other CC boards in circulation.
I have some analogue dev boards and a couple of stripped down mini sensor transmitters, and they are all essentially the same circuit board with very minor changes depending on the revision number. IE provision for a pullup resistor on the mini sensor PCB which is probably used on the optismart.
Hopefully i can give you a good idea of the connections if you can tell me the colour order etc.
Any close up pictures you may have of the plug and sensor may be of help too.