From ArticleWorld

A decoder is a device which decodes information previously encoded by an encoder, restoring original information. Technically, it does the reverse of the decoder. In general, decoding information is done using the same method. It is commonly used in digital communication and electronics.

Usage in electronics

Decoding is often required in digital electronics, for devices like segment displays, and also for various applications like memory address decoding or multiplexing. Technically speaking, decoders are logic circuits with multiple inputs and outputs, converting coded inputs to coded outputs. The output code is obviously different from the input code.

The simplest decoder is the AND gate, whose output is 1 (high) only when both all its inputs are 1 (high). Similar simple encoders exist for other elementary logical functions. More complex encoders are possible. For example, the n-to-2n binary decoders convert n-coded inputs to a maximum of 2^n unique outputs.


An endec is a device that encodes and decodes data, often using the same circuitry or algorithm. In general, only hardware is considered endec, although it actually executes the same functions that a codec would do, except that codec usually refers to software. Most emergency alert system units are endec, just like the modems.