Which character is “·−”?
Show answer
A
36 questions · Technology
Three dots, three dashes, three dots: that is SOS: probably the only piece of Morse code almost everyone knows. In this pack you turn dots and dashes back into letters and work your way from beginner to fluent reader. Morse code was developed by Samuel Morse and Alfred Vail in the 1830s and 40s for electric telegraphy, and for decades it was the fastest way to send a message across continents. Its elegance lies in a simple idea: frequent letters get short codes, rare ones long codes. E, the most common letter in English, is a single dot; A is short-long (di-dah); B is dah-di-di-dit. Legend has it that Vail counted the letters in a printer's type case to work out the frequencies: an early ancestor of data compression. Along the way you will meet the radio culture that grew around it: CQ is the general call to all stations, and CQD was the distress signal before SOS took over. Did you know that SOS does not actually stand for anything? It was chosen simply because its rhythm is unmistakable and easy to send.
Practise for freePurFact brings every card back right before you would forget it. That's how knowledge sticks.
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