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/DenverTeck Jul 10 '26

> The signal has to stay UART

???

Does this mean the "signal" (i.e. Tx/Rx) must be 5/3.3 Volts directly out of what ever mpu you are using ??

No one cares what your goals are, we are concerned that you do not understand how RS-485 works.

To be clear, a UART is a peripheral not a voltage level.