RS-485 is a differential signaling protocol. It has 3 pins, A, B and GND.
Hobby electronics often have a communication interface based on that which is used for servos. We will refer to this as the servo control protocol. The servo control protocol is a specialized type of pulse-width modulation signal. This interface is very common in both the radio control hobby and in robotics.
https://youtu.be/FeCmUwTdfH8?si=AMWzrBMEdWPbdV00