Definition
A central telephone exchange is a switching facility that routes telephone calls between users on a network. In the aviation context, CENTX refers to the dedicated telephone switching system used by the FAA and military to connect calls between air traffic facilities, flight service stations, and other operational offices.
Plain English
It's the phone hub that connects calls between FAA and aviation offices, just like a switchboard connects calls inside a large company.
Context Anchor
Seen in FAA acronym and contraction lists, and sometimes in aviation notices or facility information involving telephone service.
Derivation
Central means the middle point that everything connects through. Exchange comes from the idea of swapping or passing something from one side to another. A telephone exchange swaps a call from one line to another so it reaches the right person.
Why Pilots Care
If a notice mentions CENTX, it is usually about the telephone service or switching facility used to contact an airport, flight service, or another aviation support facility.
Intuition Check
Do not read “exchange” here as a trade or a conversation. Here it means the telephone switching point that routes calls.
Example Sentence 1
The facility directory listed the CENTX number for reaching the tower's administrative line.
Example Sentence 2
The specialist at the flight service station used CENTX to connect the pilot's telephone briefing request.