A digital circuit with standardized characteristics that operates
at 2.048 Mbps. This standard is widely used in Europe and in
submarine cables as the rough equivalent of aDS-1
(E1 provides thirty 64 Kbps channels - six more than a DS-1).
E3
A digital circuit with standardized characteristics that operates
at 34 Mbps. This standard is widely used in Europe for
intercarrier communications as the rough equivalent of a DS-3.
Earth Station
A satellite communications facility (a satellite dish and
associated equipment) located on the earth's surface (or on a
building, ship or other mobile vehicle).
Echo Cancellation
A technique used with voice circuits to isolate and filter unwanted
signal energy which accompanies analog transmissions.
Echo Canceller
A circuit feature that turns off the incoming signal while one end
of the call is talking (to avoid an annoying long distance echo).
It must be disabled for Full Duplex (simultaneous 2-way calls).
An echo canceller does not turn off the voice channel, as
stated, but electronically removes unwanted echo, while maintaining a
full-duplex channel. An echo suppressor disables the channel in one
direction or the other, depending on who is talking. Echo cancellers
must be disabled for some types of high speed modems calls, and must
also be disabled for "clear channel" data calls, such as ISDN.
Updated by: Jerry Skene, VP Business Development, Coherent
Communications Systems Corp.
EDI - Electronic Data
Interchange
An industry standard (ANSI X12, X.400) for direct computer-to-
computer information exchange.
EDOA - See Erbium-Doped
Optical Amplifier
EFS - Error Free Seconds
Egress
The method, time, circuit, or facility used to exit the
network at the call destination.
EIA - Electrical Industries
Association
Email - Electronic Mail
service (generic term)
End Office - See
Central Office
Class 5 Central Office Switch
owned and operated by a LEC.
End-To-End
Digital Transmission
All circuit elements are digital.
No modems are used to convert
digital signals to analog at any point.
End-To-End Service
Interexchange service that
extends from one customer premise to another customer premise. It
usually consists of the local
loops on each end and an IEC leg in
the middle.
End User
A person who uses (but does not necessarily pay for)
products and services, e.g. a person called by a paying customer.
Users are usually people, but could also be computers, objects,
switches or other types of computer systems or communication
equipment.
Engineering
The process or organization responsible for the skillful design,
construction, maintenance and enhancement of complex or
sophisticated systems of hardware, software, processes, etc.
Enhanced Services
Services using network facilities and computer processing that:
(1) act on the format, content, code, protocol or similar
aspects of transmitted information;
(2) provide additional or restructured information; or
(3) involve subscriber interaction with stored data.
Entrance Facility
A high-capacity circuit (such as DDS,
DS-1 or DS-3),
between the
LEC's Central Office and the IEC's Point of Presence to support a customer's dedicated local
access. There is a recurring charge rate element for each entrance
facility.
Entry Clerk
A computer system end user responsible for transcribing raw
data into a machine-readable form.
Enumeration List
A finite collection that identifies all possible (allowable)
values for a variable, field, data attribute, object type, etc.
(AT&T Divestiture - 1982 Modified Final Judgement) The provision of one-plus capability to
interLATA competitors of AT&T. Customers should be able to
reach the carrier of their choice by dialing 1+ the long-distance
number. The MFJ and
the
FCC require local exchange carriers to provide equal access (most
central offices now have this
capability). Equal Access may also refer to a more generic concept
under which the BOCs
must provide access services to AT&T's competitors that are
equivalent to those provided to AT&T.
Equal Charge Rule
A rule contained in the 1982 MFJ which required BOCs to charge access rates that do not vary with the volume
of traffic
Erbium-Doped
Optical Amplifier - EDOA
High-performance optical fiber amplifiers capable of reducing the
number of regenerators
needed over a span of fiber optic cable.
An international unit of average traffic on a facility during a
period of time (usually a busy hour). The number of erlangs is the
ratio of the time the facility
is occupied (continuously or cumulatively) to the time the facility is available.
Error-free Seconds
A measure of the quality of the signal being transmitted. It is a
percentage representing the total amount of time over a 24-hour period
that the signal contained bit errors and it is calculated using a test
pattern defined in CCITT Recommendation 0.151.
ES/9000 - Enterprise
System 9000
Large scale IBM computer system.
ESF - Extended Super Frame
An enhanced version of D4 formatting, and it is the current
industry standard. ESF is composed of 24 frames of 192 bits each. ESF
provides 16 signaling states in the 193rd bit to ensure sychronization,
supervisory control, and maintenance capabilities.
Ethernet
A LAN and data-link protocol based
on a packet frame.
Usually operating at 10Mbps, multiple devices can share access to
the link.
Event
A milestone, a signal, the completion of something that is of
interest to an object, a process, or a system
Event Driven
A system of cooperating objects that responds as things happen
in real-time. (Contrast with Batch-Oriented)
A written customer designation that certifies that its dedicated
facility should be exempt Special
Access Surcharge.
Expedite
A formal process of diverging from normal processing
procedures to accelerate the handling of a high-priority request
(usually at a higher cost to the requester).
Express Circuit
A carrier circuit set up between two cities without multiplexing
equipment, thus simplifying the provisioning process.
Extended Super Frame
(ESF)
An enhanced version of D4 formatting, and it is the current
industry standard. ESF is composed of 24 frames of 192 bits each. ESF
provides 16 signaling states in the 193rd bit to ensure sychronization,
supervisory control, and maintenance capabilities.
