The Morse key consists of a hand-operated electrical switch, a battery, and a receiver, called a sounder. Both sending and receiving circuits are grounded.
Pressing the key (switch) at the sending location sends an electric current to the antenna. The signal is picked up by the receiving antenna and electric current is sent to the sounder. At the sounder, the current magnetizes a hinged tab that connects to another with a loud click. Release of the sending key discharges the magnets and the hinged tab springs away, causing another click.
An experienced operator can send a Morse code "dot" with a quick key strike (causing two close clicks) or a long key depression for a "dash" (two more separated clicks). The transmitted message is "read" by discerning the "dots" and "dashes" and translating the code.
From Guglielmo Marconi to George A. Hoadley,
Conveying deep apprecation for the honor of
being the Franklin Medal awardee, 5/25/1918.
Thank You Letter (651K)