This made it much easier to hear the clicks and clacks. I remembered seeing a table in the Callbook that listed various telegraph codes. The letters C, F, J, L, O, P, Q, R, X, Y and Z are different. The figures and punctuation marks are different. And the elements C, O, R, Y and Z are composed of dots and spaces.
T is a short dash and L is a longer dash.
At this point I decided to enlist the aid of my computer. I played the tape into my computer's sound card and digitized the audio. I could then display the waveform and see the clicks and clacks. This was much closer to Samuel F. B. Morse's original telegraph. Morse's original invention had a clockwork that moved a paper tape.