Tap Code Converter
Convert plain text into Tap Code knock patterns or decode Tap Code back into readable text.
This classic 5x5 grid system is closely related to the Polybius square and works well for low-tech signaling.
Tap Code places the alphabet into a 5x5 square and represents each letter with two groups of taps: the first group gives the row, and the second group gives the column. For example, A is `.` `.` and T is `....` `....`.
Because the grid only has 25 cells, C and K are usually merged into one position. That is why a Tap Code decoder often returns C when you enter the pattern that could also mean K.
This tool uses `/` between letters and `//` between words so the output stays readable on screen while preserving the same row-column logic used in manual knocking.
Plain text
MEET
Tap Code
... .. / . ..... / . ..... / .... ....
Plain text
CODE
Tap Code
. ... / ... .... / . .... / . .....
Tap Code is a practical adaptation of the older Polybius square idea, which dates back to classical antiquity. In modern popular culture, Tap Code is most often linked to prisoners passing messages through walls, pipes, or bars when spoken communication is restricted.
Unlike Morse Code, Tap Code does not depend on short and long signals. It only needs countable knocks or taps, which makes it useful anywhere you can produce repeated pulses but cannot vary duration reliably.
Authoritative references
Low-Tech Signaling
Useful when only knocks, taps, or other repeated pulses are available.
Cryptography Education
Helps learners understand grid ciphers, coordinate encoding, and constrained alphabets.
Puzzle Design
Common in escape rooms, ARGs, and historical cipher challenges where hidden communication matters.