CAN Bus and RS-485

Reliable communication over long wires.

Plain UART fails over long, noisy cables. RS-485 sends each bit as the difference between two wires, which rejects noise and works over hundreds of metres with many devices.

CAN adds a message format with identifiers and automatic collision handling, so any node can talk when the bus is free. It is common in vehicles and machinery.

Both need correct termination resistors at the cable ends.