When a designer works out a PCB (like a radio receiver) he usually wants the ground line around the outside edge as far as possible to give some sheilding. Thus the outside row of connections are the gound line, usually black. The positive power rail requires a straight run as well, and is usually the next row, normally red. The signal wires need to be connected all over the PCB, and are conveniently located furthest inboard, normally the yellow wire. As there is not normally a DC path on the signal wire, no harm occurs when plugging in back-to front (just as well).
Some manufacturers had, and possibly still have, their own ideas about what order the connections should be in, and what colour the wires should be, but I have found that Futaba, Hi-Tec and Acoms conform to the same standard. Manufacturers will still try to "lock you in" by making the hole in the receiver case a different shape to anybody else's, and moulding the plug a bit differently, but it's usually nothing that a modeller with a sharp knife can't cure.
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Topic: Futaba receiver connections (Read 4960 times)