Definition
A communications device that combines multiple data streams onto a single transmission line by allocating line capacity dynamically, giving bandwidth only to the channels actively sending data at any given moment. In FAA ground systems, STMUX equipment is used to consolidate data feeds from various facilities and sensors over shared communication links.
Plain English
A piece of equipment that takes data from several sources and sends it down one line at the same time, sharing the line smartly by giving more space to whichever source is busy at the moment.
Context Anchor
Seen in FAA acronym lists and technical communications-system references, not as a normal cockpit command or flight maneuver term.
Derivation
‘Statistical’ here means the device shares the line based on which channels are actually busy, rather than giving each one a fixed slot. ‘Multiplexer’ comes from the Latin multiplex, meaning ‘many-fold’ — a device that handles many signals through one path.
Why Pilots Care
A pilot is most likely to need this term when reading FAA technical material or system-status information. It points to communications equipment, not to an action the pilot must perform in the airplane.
Analogy
Think of a single-lane road shared by several neighbourhoods, where a smart traffic controller gives the green light to whichever neighbourhood actually has cars waiting, instead of cycling through empty lanes.
Intuition Check
Do not read statistical as “doing math for the pilot.” Here it means the equipment shares a communication path according to which data sources are actually active.
Example Sentence 1
The remote facility’s data feeds were combined through an STMUX before being sent over the leased line to the central site.
Example Sentence 2
During preflight checks the technician verified that the STMUX was correctly routing sensor inputs.