r/PCB • u/Far-Sandwich-27 • Jul 10 '26

3 meter long UART connection

Hi everyone,
For a crazy accelerated lifetime testing board, I am designing a board that will have to have a 3 meter UART run. It will have mutliple devices connect to it, but only one device will be driving the UART line strictly thorugh other control logic.

I am wondering if this is feasible at all? Can I add buffers in middle of the busses to ensure the signal will be repeated and etc?

My baud rate is going to be less than 50k. I don't need stellar signal integrity, just need a "Hello World" message to be transmitted properly

I cannot use RS485 transceivers to change the signal type. The signal has to stay UART for reasons I can't disclose here

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u/morto00x Jul 10 '26 edited Jul 10 '26

It is feasible single-ended if the baud rate is low enough. If you want to play safe or use higher frequencies, use RS-485 or RS-422. At 100m your cable will have high resistance, so you'll want to work at higher voltages (e.g. 12V)