Understanding Morse code and the SOS message

Morse code is a telecommunication technique used for encoding, receiving, and sending alphanumeric and special characters by applying signal sequences with different duration. Morse code is named after Samuel Morse, a telegraph inventor. This code is important because it was commonly used for radio and wired communication over long distances, in particular, for sending and receiving telegrams. Nowadays, Morse code is still used in amateur (ham) radio communications because it can be reliably decoded by people when electromagnetic atmospheric conditions are unfavorable. More importantly, Morse code can be used in an emergency by sending SOS messages in the form of light, audio, or electromagnetic signals. Morse code is still sometimes used in aviation as a radio navigation aid.

Each character in Morse code is made with dashes (represented by the - symbol) and dots (represented by the . symbol). A dot is one signal unit, and a dash is...