Output 6 of a 74138 octal decoder is selected when it is enabled by a data input of:

A₀ = 1
A₁ = 1
A₂ = 0

A demultiplexer is a device that converts some code to a recognizable number or character.

In HDL, a process is usually thought of as a wire connecting two points in a circuit.

A four-line multiplexer must have as inputs four data inputs and two select inputs.

When data input I₁ of a 74148 octal-to-binary encoder is active, the data output is:

A₀ = 0
A₁ = 0
A₂ = 1