January 17, 2013 AT 1:20 pm

RS-232 and RS-485 guide

Adafruit 1069
A lot of us are still working with RS-232 and RS-485, so this printout would be handy to keep around (PDF).


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6 Comments

  1. Yay! Maybe this means my request for a TTL <–> RS-232 adapter is in the works! :-)

  2. note that these pin outs are only good for NI hardware and NI hardware is $$$ (but very nice). there isn’t a standard governing serial pin outs so everyone does their own thing…

  3. Actually serial pin outs are standardized. There are different configurations such as a null modem, but that too is a standardized pin out.

  4. RS-245 ?

    RS-485

  5. > Actually serial pin outs are standardized.

    The pin outs are standardized. However, in practice, what the pins are used for is not.

  6. DB9 and DB25 rs232 are standardized. Modular jacks are wildly non-standardized, and 10pin versions are pretty uncommon. Personally, I quite like the cisco 8-pin RJ45 pinout (RTS, DTR, TXD, GND, GND, RXD, DSR, CTS) (which also works using the center 6 pins), but … that’s personal, and it’s been pointed out that it doesn’t map well to standard building UTP schemes. It does let you plug one rj45 directly into another using a standard "rolled" flat cable.

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