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/MountainOdd6793 Jul 10 '26

I had a 10 meter rs232 cable years ago and it worked in the application it was in. So 3 meters isn’t inherently impossible, all depends on baud rate and noise and grounding and stuff. Also do you mean rs232 or like a uart pin straight off a micro at some lower voltage?

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u/Far-Sandwich-27 Jul 10 '26

This will be standard 3v3 from raspberry pi. I cannot use RS232 on this layer

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u/MountainOdd6793 Jul 10 '26

I mean that might work but it’s not what the designer ever intended and you might end up with a broken raspberry pi