Beeps and tones

Two of the most common ways to hide a message in a sound are Morse code, as short and long beeps, and touch-tone (DTMF) dialing, the sound a phone keypad makes. CacheCrack listens to the sound, measures the beep lengths for Morse, and picks out the two-tone frequencies of each DTMF digit, then turns them into text and digits.

It also shows the plain Morse dots and dashes in case a letter did not come through, so you can read it by hand.