Communication Systems

Semaphore Line
Also called a semaphore telegraph, optical telegraph, shutter telegraph chain, Chappe telegraph, Napoleonic semaphore. Consisting of a tower with pivoting shutters, blades, or flags, information is encoded by the position of mechanical elements. Similar to a signal fire but with more semantic possibilities. Much faster and cheaper than post riders, replaced after a half century by the electrical telegraph. (Invented in 1801.)

Derivatives include flag semaphore and the heliograph.

Q Code
A standardized collection of 3-letter codes all beginning with "Q", used in radiotelegraph communication. Originally used in conjunction with Morse code. QAA-QNZ: aeronautical use, QOA-QQZ: maritime use, QRA-QUZ for all services. Some other brevity codes: Z code, police Ten-code, RST specifically for communicating the quality of a radio signal, multiservice tactical brevity codes(sure is a long name for a brevity code), related to voice procedure.