I was very confused about this at one time. Then I learned that modern servos and ESCs are basically universal, in that they will all work with any receiver. This discovery made life a lot simpler!

There are some small differences in the connectors used by Futaba, JR, Hitec, and Airtronics. But the pinouts and pin spacing are the same for all. I've had one instance where I had to trim a bit of plastic from a servo connector to allow it to fit into a receiver, but otherwise they are all compatible.

- Jeff