Four-Tone Code

Text to tones and back.

The four pitches · click to hear

Encode

Text

Speed

Tone, ms

Gap in a symbol, ms

Gap between symbols, ms

Pitch set

Instrument

Ending Add ∎ End of message

Code length 3 tones only

Source

Choose a file or drop a .mid, .zip or recording (.mp3, .wav, .m4a) here

Pitch set

Speed

Code length

Click a cell to hear it.

Each character is three tones: the 1st picks the table, the 2nd the row, the 3rd the column. For example, H = 1 2 4.

Every character and key. A dot means it also has a short code.

With "3 tones only" off.

Listen, then type what you heard. Uses the Encode settings.

Practice

Characters from

Press Next to hear the first one.

Accuracy by character

Weaker characters come up more often. Progress is kept in this browser.