Serving area interface

From Wikipedia, the free encyclopedia
Jump to: navigation, search
SAI in New Jersey

The serving area interface or service area interface (SAI) is an outdoor enclosure or metal box that allows access to telecoms wiring.

Alternate Names[edit]

  • Access Point (AP)
  • Cabinet (Cab)
  • B-box
  • Cross box
  • Cross-connect box
  • Pedestal (Ped)
  • Primary Connection Point (PCP) (UK)[1]
  • Secondary Connection Point (SCP) (UK)[2]
  • Telecom Cabinet


The SAI provides the termination of individual twisted pairs of a telephony local loop for onward connection back to the nearest telephone exchange (US: "central office" (CO)) or remote switch, or first to transmission equipment such as a Subscriber Loop Carrier multiplexer and then to the exchange Main Distribution Frame (PDF).

In UK, the components from PCP onwards to customer are known as "D-side" (Distribution Side), and from PCP back to MDF the "E-side" (Exchange Side). In the US, the connection back to the MDF are known as F2 (Secondary Distribution Cable) and/or F1 (Main Feeder Cable) pairs.

SAI are used in suburban and low density urban areas, serving some of the same purposes that manholes do in high density urban areas. Besides a cross connect point, they sometimes contain a DSLAM or more rarely a remote concentrator or both.


  1. ^ "Multimedia Telecommunications" (BT Telecommunications Series), B. Whyte (Ed.), Springer 1997
  2. ^ "Multimedia Telecommunications" (BT Telecommunications Series), B. Whyte (Ed.), Springer 1997

See also[edit]