Worth pointing out that there are designed for use on a 2-wire bus; not sure what OP is using.Try using RS485 transceivers with auto-direction feature, e.g.
https://www.ti.com/lit/ds/symlink/thvd1426.pdf
https://www.analog.com/media/en/technic ... 13488e.pdf
Just swap the chip and pull pin 3 (former DE, now !SHDN) permanently high. Should be easy being only a SO08 package.
Personally I'm somewhat wary of this type of device, since random noise could potentially trigger the direction sensing. Its also not possible to ensure that the transmitter is enabled with a setup time before sending the first character. Clearly they work at least 'well enough' for some. (I have found them pretty reiable in a benign environment).
Statistics: Posted by stevend — Sat Dec 20, 2025 12:53 pm