Summary

Morse code is a telecommunication method used to encode text characters as sequences of two different signal durations—short and long. These signals, known in Morse code terminology as "dots" (short signals) and "dashes" (long signals), can be transmitted in various forms such as sound, light, or electrical impulses. Developed by Samuel Morse in the 1830s, Morse code became a fundamental communication tool in maritime, military, and amateur radio contexts, though its use has declined with the rise of digital communication technologies.

How it works: Encryption

Each letter of the alphabet, numeric digit, and common punctuation mark is assigned a unique combination of dots and dashes. For example, the letter 'A' is encoded as ".-", and 'B' as "-...".
To prepare a message for transmission, each character in the text is replaced by its corresponding Morse code sequence. Spaces between words are usually indicated by a slash ("/") or by a longer pause than that between letters. The encoded message is then sent using the chosen medium, be it auditory signals like beeps, visual signals like flashes of light, or physical signals like electrical pulses.

How it works: Decryption

The receiver listens to or observes the sequence of incoming dots and dashes. Each sequence of dots and dashes representing different characters is identified. The presence of a standard pause (typically three times the duration of a dot) indicates a space between letters, and a longer pause (seven times the duration of a dot) indicates a space between words. The sequences are then converted back into their corresponding characters using the Morse code alphabet.

There important practical applications include:
Start/End Indicators: Often, Morse code messages start with a specific sequence (△ -.-.- for "Starting Transmission") and end with another (▽ .-.-. for "End of Transmission").
Special Codes: Some sequences have specific meanings, like the distress signal "SOS" (…---…), which is universally recognized.

References

[1] Youtube video, "Invention of the Telegraph" - Online source.
[1] Wikipedia, "Morse Code" - Online source.