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Communication code

Concept

A code maps agreed signals to meanings that a receiver can recover.

Explanation or usage

A sender encodes a message and a receiver interprets signals using a shared mapping. The same meaning can travel through different media when the signals remain distinguishable. A code enables communication; it is not necessarily secret or encrypted.

Common misunderstandings

Every code is designed to keep a message secret.

In Code

General context reviewed · book attribution and sources pending

Flashlight signaling can illustrate shared encoding: a sender and receiver use an agreed mapping between signals and meanings.

Linked books

Practice this item

Illustrative message system: a sender flashes a lamp twice, but the receiver has never learned the mapping. What is missing for reliable decoding? Why can a dot-and-dash message be transmitted through sound or light? Why does counting 64 six-dot patterns not imply there are 64 distinct alphabet letters?