8

RxD means Receive Data.

TxD means Transmit Data.

Where the "x" come from?

Bumzy
  • 127
  • 1
  • 1
  • 8
  • 7
    Rx is short for receive because I guess someone decided it was easier than writing "receive" all the time. Likewise for Tx/transmit. It's not specific to electronics, you see e.g. pilots saying "pax" for "passengers". – user253751 Jan 30 '16 at 13:01
  • 6
    This sort of word etymology question would probably be better on English.SE, in fact there's a related question that probably at least partially answers it: http://english.stackexchange.com/questions/229929/what-is-the-origin-of-tx-as-an-abbreviation-for-transaction/229934 – PeterJ Jan 30 '16 at 13:05
  • 3
    I suspect the word "exchange" has something to do with it. See also PABX and MUX. But X could also mean "cross". – Andy aka Jan 30 '16 at 13:14
  • 1
    @PeterJ That's an unusually sparse answer for ESE. The use of x as an abbreviation is much older than the technological examples given. Consider Rx (for prescription, which is short for Latin recipe). This is different from the X in Xmas, where X is the first letter of the Greek spelling of Christ (Χριστός). – Spehro Pefhany Jan 30 '16 at 14:40
  • http://english.stackexchange.com/questions/37394/why-do-some-words-have-x-as-a-substitute – Andy aka Jan 31 '16 at 11:33

1 Answers1

10

Comes from the 'good old days' of radio when Morse code ruled. Abbreviations abounded (c.f. text messages!), and TX was transmitter or transmit; RX was receiver or receive \$\cdot\cdot\cdot-\cdot-\$

Chu
  • 7,586
  • 2
  • 15
  • 16
  • 2
    "TT" or "RR" would be shorter in Morse code than "TX" or "RX". So why "X"? You might be right, but as a statement, this does not seem very compelling. One can argue whether etymology questions are suited for EE.SE, of course, but either way this is not an answer to such a question. – Oleksandr R. Jan 30 '16 at 16:07
  • Try "beef essence" in Morse :-) – Russell McMahon Jun 23 '21 at 09:32