A demarc extension bridges the physical gap between the telecommunications provider's demarcation point (where their responsibility ends) and the customer's edge equipment, such as a router or PBX. It typically consists of copper or fiber-optic patch cables running through a building's conduits from the main telco closet to a specific suite or server room.
The ISP installed the fiber in the basement, so we need a contractor to run a demarc extension up to our server room on the fifth floor.
Service providers rarely troubleshoot past the demarc; if the extension fails, it is entirely the customer's responsibility to fix.
Also heard as
- inside wiring
- extended demarc
Related terms
CPE
Telecommunications hardware located at the subscriber's physical location rather than the provider's facility.
Local loop
The physical wiring connecting a customer premises to the nearest telephone exchange.
Meet-me room
A secure area in a data center where telecommunications companies physically interconnect their networks.