A recognition signal is a

signal A signal is both the process and the result of transmission of data over some media accomplished by embedding some variation. Signals are important in multiple subject fields including signal processing, information theory and biology. In ...

whereby a person, a

ship A ship is a large watercraft, vessel that travels the world's oceans and other Waterway, navigable waterways, carrying cargo or passengers, or in support of specialized missions, such as defense, research and fishing. Ships are generally disti ...

, an

airplane An airplane (American English), or aeroplane (Commonwealth English), informally plane, is a fixed-wing aircraft that is propelled forward by thrust from a jet engine, Propeller (aircraft), propeller, or rocket engine. Airplanes come in a vari ...

or something else is recognized. They can be used during war or can be used to help the police recognize each other during

undercover A cover in foreign, military or police human intelligence or counterintelligence is the ostensible identity and role or position in an infiltrated organization assumed by a covert agent during a covert operation. Official cover In espionage, a ...

operations.

War

These signals are often used to recognize friends and enemies in a war. For

military A military, also known collectively as armed forces, is a heavily armed, highly organized force primarily intended for warfare. Militaries are typically authorized and maintained by a sovereign state, with their members identifiable by a d ...

use these signals often use colored lights or the International marine signal flags.

Police

Other uses of the signal include the police who sometimes use a recognition signal so that officers in

uniform A uniform is a variety of costume worn by members of an organization while usually participating in that organization's activity. Modern uniforms are most often worn by armed forces and paramilitary organizations such as police, emergency serv ...

can recognize officers in normal clothing (undercover). The

NYPD The City of New York Police Department, also referred to as New York City Police Department (NYPD), is the primary law enforcement agency within New York City. Established on May 23, 1845, the NYPD is the largest, and one of the oldest, munic ...

often use

headband A headband or hairband is a clothing accessory worn in the hair or around the forehead, usually to hold hair away from the face or eyes. Headbands generally consist of a loop of elastic material or a horseshoe-shaped piece of flexible plast ...

s, wristbands or colored

clothing Clothing (also known as clothes, garments, dress, apparel, or attire) is any item worn on a human human body, body. Typically, clothing is made of fabrics or textiles, but over time it has included garments made from animal skin and other thin s ...

as recognition signals which are known as the " color of the day".

References

External links

Signalman manual
{{DEFAULTSORT:Recognition Signal Communication Biological techniques and tools Military communications

War

Police

See also

References

External links