Just last week I was replacing some old sensormatic PTZ domes (from the 90's) which used a four wire RS-422 loop for PTZ control. Two for transmit, two for receiver. They were being replaced with new American Dynamics PTZ.
Last year some one else had replaced about five of these cameras at the same place, so I checked their wiring, they were using the orange and the yellow from the red/green/orange/yellow four conductor cable sensormatic ran.
I replaced my first camera, with some difficulty before I looked at another one and realised I had my new one set for SensorNet, instead of RS-422. Changed the sip switches on the camera, and it worked fine.
I go to do the next one, did everything the same as the first, only pre-set to RS-422 this time. But nothing. I tried a few power cycles, tried a few re-wires and different PTZ addresses, but nothing. So I take a break, go do a few other cameras (no problems), and then come back to this one and just replace the unit. New unit goes up without a problem.
I figured I had a bad camera, no big deal. I had two more cameras to replace, told the customer we might not be able to do the last one. I go to install the next one and I have the same problem. So this time I look all over the old Sensormatic PTZ and google what ever numbers that resemble a model number, and manage to find what looks like an installation guide. In the guide it indicates Orange and Green are receive +/- and Red/Yellow are transmit +/-. So I change my yellow wire to green and everything works. I wire up the camera I thought was bad, and it also works.
So I had three cameras in total that would only work when wired properly, but there are an additional 6-7 throughout the store all wired wrong, but working a hundred percent. One location where one camera wouldn't work with orange/yellow (Receive +, Transmit -) but a second camera did.
It was very strange...I'm not sure if some one wired something wrong on the distribution block I found in the ceiling (presumably from original sensormatic installation), or if it was just hit and miss. But everything was working so I left it.