RS-422 e RS-485

RS-422 (EIA-422, TIA-422)
Differential point-to-point communication (4 wires)
Voltage: +/- 5V (from 2V up to 10V), 4kOhm load on RX side
Up to 10 receivers for each transmitter
100kb over 1200m, 10Mb over 12 m

RS-485 (EIA-485, TIA-485)
Multi-point differential communication (2 wires)
A single transmitter at a time
Differential signalling (1.5V to 5V)
Up to 32 devices on each bus
100kb su 1200m, 10Mb su 12m
This 485 variant is the most used industrially
If you connect to a UART, you use RTS or CTS or a GPIO
There are external transceivers
Some UARTS have internal RS485 support
The TX-off timing is a critical factor