Aircraft wire, pretty much all PTFE, either solid or foam, and the connectors are coded by various means, orientation of the inner in relation to the body, or with various arrangements of the guide slots and grooves in the outside, and of course also with some in the same shell size and orientation, but with different pin diameters for some of the pins. Those ITT Cannon connectors all come from the manufacturer with a kit, which has the connector shell, and with it a small transparent bottle with a red lid, containing the exact number of pins for that connector, plus the same number of blanking plastic plugs, used when you are not using the full complement of pins electrically, to fill the holes in the shell, along with a small plastic tool, red on half and white on the other half, which is a single use insert extract tool used to place them in the shell after you have crimped or soldered the wires into the rear of the pins.
The 115 VAC 3 phase AC system is dropped down in many places to a 28VAC 3 phase 400Hz voltage, used to power many of the resolvers and synchros that are smaller, along with having in many avionics boxes a separate 6VAC 400Hz transformer, driving the input devices, whether they are resolvers, synchros or even pots, which are all AC excited. This 6VAC is also used as a phase reference for the systems, as the most common way to convert your input into an analogue voltage, before it is digitised, is to use the 400Hz reference to drive a series of analogue switches, that sample the inputs at the peak of the waveform, along with the reference voltage, to give a ratiometric conversion that will be accurate irrespective of the actual bus voltage.
Yes those plugs are oriented differently, and getting any variety other than your standard orientation was always a massive pain, as the variants are not always available, or are often just a cross reference to the base number, so no matter what orientation you order you get the base part. If you just needed the pins no problem, just toss the rest, but if you actually needed that shell it was a bit of a pain.