Sign

Foco for communication by light signals.

A signal is a sign, gesture, or other kind of report or notice of something. The signal replaces, therefore, the written word or language. They obey conventions, so they are easily interpreted.

When it comes to symbols, signs are placed in conspicuous places and are usually made in various colors and shapes. In the case of gestures, they are made by people through their hands and arms. There are also indications consisting of flags, used above all in maritime navigation, and light signals, such as those of lighthouses on the coast.

Likewise, a signal can also be the variation of an electric current, or another physical magnitude that is used to transmit information. For example, in telephony there are different signals, which consist of a continuous or intermittent tone, at a characteristic frequency, which allows the user to know what situation the call is in.

According to Escandell Vidal, a signal is a perceptible modification of the environment produced to communicate. We can use as signals any type of external stimulus such as: linguistic expressions, gestures, drawings, clicks, among others.

Types of signals

• Electric signal
• Analog signal
• Digital signal
• Signal (informatics)
• Signs of maritime flags
• Railway signs
• security signals
• Traffic signs