Decode DTMF and Morse#
Neither decoder has settings, so telephone keypad tones come back as digits and keyed tones come back as text on a single run.
DTMF and Morse are the two decoders that need nothing from you but a run. Neither has settings. Point them at a range and select Decode.
Read DTMF digits#
DTMF is the touch-tone signalling used on telephone keypads. Each key sounds a pair of tones together. The decoder returns the digits in the order it heard them, with a badge that counts them.
On a spectrogram, DTMF is easy to spot before you decode: short bursts, each made of two clean horizontal lines stacked at different heights. If the result comes back empty, check that the range you selected covers those bursts, and that you have the right channel on the toolbar.
Read Morse text#
Morse returns the decoded text directly.
Morse decoding depends on a tone that stands clear of the background, so tune the display first. The spectrogram then shows you whether the keying is clean. A narrow Range on the toolbar suppresses noise and makes the dots and dashes obvious as separated bursts on a single frequency. If the text comes back garbled, a selection tight around one transmission usually does better than the whole file, especially when the sending speed changes part-way through.