Yes I forgot about it, have done/added a BJT recently to invert for some electricity meter protocol. For SoftwareSerial, it should be possible to be done without HW inversion, is long time ago I did that on TI C64xx DSP in assembly (in interrupt handler), but now even ChatGPT could maybe generate (pseudo) C-code that works on Arduino or similar.The logic is also inverted.You could use diodes, zeners, resisters etc to reduce RS332 voltage levels to 3V3 TTL levels.
Also have no active RS232 around anymore although still have the good old null-modem cable with 2x DB25 and also adaptor to DB9. Used a lot for filetransfer (and whole floppy images as well).
Statistics: Posted by redvli — Fri Jul 11, 2025 11:51 am