An alfa is a representation of the letter A in the ICAO radiotelephony spelling alphabet.

Signals can be sent by flaghoist, signal lamp ("blinker"), flag semaphore, radiotelegraphy, and radiotelephony.

Italian inventor Guglielmo ( Bill, to Yanks) Marconi is generally considered the founder of Radio- largely radio-telegraph from l895 to about the turn of the century- radiotelephony- Voice radio- and in a sense the forerunner of both Broadcasting and eventually- Cell Phones came out later- but there were practical tests by Canadian engineer Fessenden.- around l906-08.