Received a nice return QSL card from Paco in the Canary Islands this morning for a QSO we had in February. Under mode, he filled in "A1A" to indicate CW. I see that is ITU classification for method of modulation (double-sideband amplitude modulation), nature of the modulating signal (one channel containing digital information, no subcarrier), and type of information transmitted on the carrier signal (aural telegraphy, intended to be decoded by ear, such as Morse code).

https://en.wikipedia.org/wiki/Types_of_radio_emissions

Never seen that before. It's cool, and I am sure CW ops love it for its superior way of expressing Morse code--A1A :-).

Always something to learn.

73,

Scott/W5AAJ