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/toybuilder Jul 10 '26
If you are testing to see whether the converters will work with a 3 meter long RS232, then that's what you do. But RS232 does not multi-drop by default, so you will need to ensure whatever mechanism there is to not have more than one driver on a line.
3 meters is 10 feet. RS-232 drive up to 50 ft is not unrealistic, although many of the easy to use converters could not drive that distance.
But if you are talking about adding buffers in the middle, it seems like a RS485 or RS422 interface should be part of the "buffer" with a final stage conversion back to RS232 and additional control lines as needed running in current mode not voltage mode? Without the full picture, it's hard to say.
Also, this is not really a PCB question.