电信专业英英词典E-4（在线收听）

　　electromagnetic interference; also, exchange message interface

　　End Office (EO)

　　EO is a LEC (BOC or an ITC) switching system within a LATA where local loops to customer stations are terminated for purposes of interconnection with each other and with trunks. CO (central office) and EO are often used interchangeably.

　　Entrance Facilities

　　1. in a premises distribution system, the point of interconnection be tween the building wiring system and external telecommunications facilities (LEC networks, other buildings, etc.). Bellcore defines the interface with LEC networks as end-user points of termination (POT). 2. has a further specific meaning in interstate access, entrance facilities for interstate access (ENFIA).

　　EO

　　end office

　　EPSCS

　　enhanced private switched communications service

　　Equipment Room

　　In a premises distribution system, an equipment room is a special purpose room(s), with access to the backbone wiring, for housing elecommunications, data processing, security, and alarm equipment.

　　erlang

　　An erlang is an international dimensions unit of the average traffic intensity of a facility during a period of time; one erlang of traffic is equivalent to a single user who uses a single resource 100% of the time. See centicall seconds.

　　ESF

　　extended superframe

　　ESN

　　electronic switched network

　　Exchange Carrier (or local exchange carrier LEC)

　　An exchange carrier is any company, BOC or independent which provides intra-LATA telecommunications within its franchised area.

　　Extended Superframe Format (ESF)

　　ESF is an extension of the superframe format of T1 carrier systems from 12 to 24 frames and the use of framing bits for error checking, a facilities data link (FDL) as well as frame synchronization. See superframe format.