They have male DIN-4 connectors on both ends, and four-conductor cable. They are wired straight through: pin 1 to pin 1; 2 to 2; 3 to 3; and 4 to 4.
In the ones I have, looking at the back of the connector with the pins pointing away from you, going clockwise from the alignment notch, the wires are colored yellow, green, red, and white.
The shell opens up pretty easily. There is a squarish tab in the outer plastic shell that can be lifted up with a small screwdriver. While holding that up, the plastic shell can slide back along the cable. With that out of the way, the two halves of the metal shell come apart easily. One of those halves is crimped onto the cable, and the other half is loose. You can then see the wiring, or hack on it.
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