Definition
A communications device that combines several separate data streams onto a single transmission channel by giving each stream a brief, repeating time slot of its own. Each input takes its turn to send data, and the receiving end reassembles the streams in the same order so they arrive as if they had each travelled on their own line.
Plain English
A piece of equipment that lets several data signals share one line by taking turns. Each signal gets a tiny slice of time on the line, one after another, very quickly, so that all the signals appear to flow at once.
Context Anchor
Seen in aircraft electronics, communication equipment, data-system diagrams, maintenance documents, and acronym lists; most pilots will meet it in written equipment information rather than as a cockpit control.
Derivation
From 'time division' (dividing the use of a line by time rather than by frequency) and 'multiplexer' (from Latin 'multi-' meaning many, and 'plex' meaning fold or layer — a device that folds many signals into one). Knowing this, the term simply describes a device that layers many data streams onto one line by splitting time between them.
Why Pilots Care
A pilot usually does not operate a TDMUX directly, but the term can appear in aircraft equipment information or maintenance writeups when a data or communication problem is being described.
Analogy
Think of a single-lane road with a traffic controller waving cars through one at a time from several feeder roads. Each feeder gets a quick turn, and because the turns come so fast, traffic from every feeder keeps moving steadily down the single lane.
Intuition Check
Do not read “time division” as flight scheduling. Here it means data signals are assigned small repeating time slots on one shared path.
Example Sentence 1
The TDMUX allowed several radar feeds to share one communication line between the remote site and the air traffic control facility.
Example Sentence 2
Technicians verified the TDMUX timing to restore proper data flow on the avionics bus.