A straight key is the common telegraph key as seen in various movies. It is a simple bar with a knob on top and a contact underneath. When the bar is depressed against spring tension, it forms a circuit and allows electricity to flow… Transmission speeds vary from 5 words (25 characters) per minute, by novice operators, up to about 30 words (150 characters) per minute by skilled operators.
Its clicks are a form of communication called Morse Code.Consider Morse code a sort of texting invented over 130 years earlier than the invention of texting. Each letter is represented by combinations of dot and dashed tones, lights, or clicks, and to decode the full message, you need to recognize each letter’s combo. After you’ve watched it once, play it again with your eyes closed. Hear the patterns?
Bonus: it makes a great “secret” language. Here’s the entire alphabet: See and Hear Morse Code.