SESKStuff Everyone Should Know
SESK: Stuff Everyone Should Know · sesk.info/hamg-g8c11

What are the two frequencies of a frequency shift keyed signal called?

Mark and space.

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  1. Dot and dash
  2. On and off
  3. Mark and space ✔

Why: In FSK the two frequencies are called mark and space. Dot and dash belong to Morse code, and on and off describes simple keying.

Huh, didn't know that: Baudot code is a 5-bit code with additional start and stop bits.

The dad joke
Mark and space only ever meet in turns, which keeps their relationship interesting.
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References

Answer: Mark and space. In FSK the two frequencies are called mark and space. Dot and dash belong to Morse code, and on and off describes simple keying.

  1. NCVEC 2023-2027 General Class Pool and Syllabus (6th Errata, Feb 4 2026) ncvec.org/downloads/General%20Class%20Pool%20and%20Syllabus%202023-2027%20Public%20Release%20with%206th%20Errata%20Feb%204%202026.pdf
    D. Mark and space
    Checked 2026-10-11.
  2. NCVEC 2023-2027 General Class Pool and Syllabus (6th Errata, Feb 4 2026) ncvec.org/downloads/General%20Class%20Pool%20and%20Syllabus%202023-2027%20Public%20Release%20with%206th%20Errata%20Feb%204%202026.pdf
    C. A 5-bit code with additional start and stop bits
    Checked 2026-10-11.

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