Fire Alarm and Detection Practice Test

Multiplexing is the process of carrying several signals on a single signaling line while keeping each signal distinguishable so the receiver can identify and separate them. A multiplexer combines multiple channels into one stream, and a demultiplexer at the destination recovers each channel with its identity. That matches the description of receiving multiple signals on one line with positive identification for each signal, because the system must know which signal came from which source.

Modulation is about altering a carrier to carry one signal, not about handling multiple channels on one line. Frequency-division signaling uses different frequency bands for different signals on the same medium, which can carry multiple signals but relies on frequency separation rather than explicit channel identities. Time-division multiplexing is a specific way to implement multiplexing, allocating time slots to each signal; the general concept of multiplexing covers the idea of multiple signals with identifiable identities on one line.