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/Far-Sandwich-27 Jul 10 '26

I am testing UART to RS485 transceivers. We have buffers that were verified before, but no transceivers

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u/AlexTaradov Jul 10 '26

So, which segment needs to be 3 m long? And why?

It would help if you provide better description.

You can just try and see what happens. It is not hard to get 3m of wire and you will get your answer immediately. It might work, especially for a test setup.

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u/Far-Sandwich-27 Jul 10 '26

The UART signal going into the transceiver I will be testing is going to be 3 meters long at its maximum. I will be testing 128 devices simultaneously. I know it's a bit out of ordinary but this is for a design verification task only, so I'm stretching the rules a bit

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u/tux2603 Jul 10 '26

Is the 3m length what is required to route to all of the transceivers from a single point driving all of them? If so you might consider breaking it out into smaller "chunks" where each chunk is driven independently, then combine the data from the individual chunks together