Category: History & Uses

Short uniform knocks can survive echo and clang better than tone-based Morse.

Run safe encode-decode drills for youth groups and cipher intro units.

Compare tap code with other low-tech signals used when radios fail.

See how tap-style codes appear in novels, films, and puzzle stories.

Understand wall taps, timing, and alphabet limits in confined communication.

Learn how American prisoners used knock code through walls during the Vietnam War era.