Morse code
Appearance

Morse code is a method o transmittin text information as a series of on-off tones, lichts, or clicks that can be directly unnerstuid by a skilled listener or observer without special equipment.
References
- ↑ "International Morse code Recommendation ITU-R M.1677-1". itu.int. International Telecommunication Union. October 2009. Retrieved 23 December 2011.