Commercial camera pinout connections

Aug 26, 2012 13 Replies

I have a commercial camera + LCD display package and what I am trying to do is use just the camera part, with my double din unit which includes an LCD display all ready to accept a reversing camera input.



The camera has one of those tiny DIN type round plugs on the end of its cable, with four pins rather like an S-plug.



Obviously I need to either work out the pin out of the plug or cut the plug off. So far I have broken into the side of the cable and I was expecting to see video, 12v and ground wires.



Instead what I have found is(this is measured relative to ground):-



A Reddy/orange wire which carries 12v A black which shows 2.1v A white which shows 3.4v



A screened yellow, which is obviously the video out. Its screen is at ground potential, but I confused by the voltages on the black and the white. The camera has no IR LED illumination, but I suppose the wires might include the feeds for such. I am also puzzled as to why the screen seems to have been used for the ground, if indeed it has, because it is more usual to provide a proper separate wire for the ground.



Another more industrial camera I have, has an identical plug and does include IR LED lighting. It is the same type as often seen on tipper and skip lorries.


Harry Bloomfield pretended :

I think I have this sorted now - thanks for reading.

Aw go on, d'nah keep us in suspense. What did the black and white do?

Nothing at all, they were just there to make up the numbers (?)

They were not connected at the plug, just screen/ground, video and 12v.

Why was there voltage on the wires if they were only for show?

That's all I use but I don't get readings for voltages that are not present.

No but a voltage being present isn't necessarily relevant, it can just be capacitive or inductive pickup from another adjacent cable.

Maybe but a meter saying that there is voltage there which isn't is no use to man or beast. I wouldn't have thought there would be anything like enough capacitance or inductance between cables on a car to cause false readings anyway. I suspect actual electrical leakage, the meter being misused or a very very cheapo meter.

It's a real voltage with a very high impedance.

High impedance digital voltmeter and some inductive/capacitive voltage pickup from active wires - I fell for the trap. lol

A very expensive Fluke five digit meter and it is a problem common to all high impedance meters - something always to be wary of, but despite my experience it caught me out. To be fair I didn't know what I was looking for or expecting whilst testing.

Pick up any high impedance voltmeter and turn it onto a low ac range. touch one of the probes with a finger and you will see some voltage in the display. The voltage is inductive/capacitive voltage at 50Hz picked up by you from your local mains wiring.

It is a very real voltage, but there is no or very little current behind it, so a low impedance voltmeter would not react to it - it would simply short out the tiny voltage.

OTOH a very high impedance meter is a good thing as it places a very small load on the circuit to be measured and if thats a very small voltage or current source then that measurement can be more accurate...

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