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There were two main types: the drum printer and the chain printer. The drum printer was cheaper and therefore much more common. The drum, which contained all the characters in a given font, rotated once for each row printed. An entire row was printed simultaneously; a separate solenoid-driven hammer in each column fired at the right instant to print the desired character in that column. You could easily tell from across the room whether your program had failed to compile or if execution ended with a core (!) dump. The burst pages between jobs had their own highly characteristic sound.
A related sound is that of ripping fanfold line printer paper to separate jobs. Who uses any kind of fanfold paper these days? Or even paper...?
Oh, and let's not forget the sound of the Hollerith (IBM punch card) reader...
Besides LORAN-C, there used to be another low frequency radio navigation system even better suited for global shipping: Omega. It operated on even lower frequencies, in the 10-14 kHz (yes, kHz) range, and had worldwide reach unlike LORAN-C which was only regional. It was shut down in 1997.
Jamming and spoofing are the much bigger threats.