I first of all thanks for a great book.
Bare in mind I’m on linux (mint/ubuntu isadora/lucid lynx) as the unofficial deb packages does not yet support UNO, so there is a workaround which is to create a new definition in boards.txt and change the upload speed to 115200. Also I had to symlink ttyAMC0 to ttyUSB0, or I could add some official jars from >0019 for discovery apparently.
Anyway I’m not sure what the problem is but the morse code is not really working consistently. In that I get odd delays where is no space. Dits and dahs can be often slurred into on tone. This odd timing seem to be reflected on the serial monitor ie. chunked output and non space delays. Sometimes it sounds like morse code, but it revert to not reflecting the actual dits an dahs.
I’m using your download code. I changed to reflect the buzzer as in what you book says as well as commented out code. Neither made any difference. I did increase the dit length and the made it clearer when thing are working. Baud rate is 9600.
I wonder if this is serial issue or what?