Glossary E0-A | B | C-Cn | Co-Cz | D | E | F-G | H-I | J-L | M | N-O | P-Q | R | S | T | U-Z
0-A | B
| C-Cn | Co-Cz | D | E | F-G | H-I | J-L | M | N-O | P-Q | R | S | T | U-Z
- E: Voltage (electromotive
- E-Mail: See Electronic Mail
The European equivalent to the North American T1 carrier trunk. E1 users a
2.048 Mbps transmission rate.
- Earth: British terminology for
- EBCDIC: See Extended Binary
Coded Decimal Interchange Code
- Echo: The name given to the ICMP
packets used to check the reachability of nodes or devices on a network system.
These packets are sometimes referred to a "Ping" packets.
See Entry Emulator High Level Language Applications
- EFF: See Electronic Frontier
- EGP: See Exterior Gateway
- EIA: See Electronics Industry
- EIA RS-455: The EIA “Standard Fiber Optic Test
Procedures for Optical Fibers, Cables, Transducers, Connecting & Termination
Devices”, RS-455 includes Fiber Optic Test Procedures (FOTP) for many of the
mechanical & optical requirements of optical fiber
- EIA/TIA-568: EIA/TIA-568A The
latest version of the “Commercial Building Telecommunications Wiring Standard”
which has become one of the dictating standards for copper & fiber
- EISA: See Extended Industry Standard
- Elastomer: Any material that will return to its
original dimensions after being stretched or distorted.
Closet: A floor-serving facility for housing electrical equipment, panel
boards & controls. The closet is the recognized interface between the
electrical backbone riser & its associated pathway.
Ground: One of four functions categories of DTE-DCE interface signals.
These signals provide common electrical points & discharge static & harmful
- Electromagnetic: Referring to the combined electric &
magnetic fields caused by electron motion through conductors.
- Electromagnetic Interference: (EMI) Refers to the
electrical & magnetic signals generated & transmitted by electronic &
electrical equipment. Electromagnetic signals from some sources are strong
enough to interfere with the proper operation of electronic equipment such as
net working devices.
- Electron Volt: A measure of the energy gained by
an electron falling through an electric field produced by one volt.
- Electronic Frontier Foundation: (EFF) A foundation that
addresses social & legal issues arising from the impact of computers on
- Electronic Mail: (E-Mail) An application
with which users can send information to other users with whom they share a
data communication connection.
- Electronics Industry
Association: (EIA) An organization responsible for establishing
communication signal characteristics.
- Electrostatic: Pertaining to
static electricity, or electricity at rest. An electric charge, for
- EMF: Electromotive force (voltage).
- EMI: See Electromagnetic Interference
- EMI/RFI: See Radio Frequency Interference
The imitation of all or part of one device, terminal, or computer by another,
so that the imitating device accepts the same data, performs the same
functions, & appears to other network devices as if it were the imitated
- Encapsulate: A basic protocol layering technique. The
information from a higher level protocol (which may include both data &
headers) is carried as the data portion of lower-level protocol, which adds its
own header information. For example, IP datagrams are encapsulated in Data Link
- Encoding/Decoding: Organizing information into a format
suitable for transmission, & then reconverting it after transmission; for
pulse-code modulated voice transmission, the generation of digital signal to
represent quantized samples, & the subsequent reverse
- Encryption: The basis of network security. Encryption
encodes network packets to prevent anyone except the intended recipient from
accessing the data.
- End of Text: EXT
- End of
Transmission: (EOT) A control character in Data Link Control (DLC). EOT is
sent by a DTE to indicate conclusion of transmission.
- End of Transmission Block: (ETB) A control character in the
DLC, ETB indicates the end of an "Immediate" block.
- End-to-end: An
expression used in the networking environment to indicate communication between
source & destination nodes on a network system. End-to-end communication is
carried out by the transport layer of TCP/IP.
Small Device Interface: (ESDI) an Interface type for computer adapter &
- Enterprisewide Network: A Internetwork connecting
all sites of a single corporation worldwide.
Emulator High Level Language Applications Interface: (EEHLLAPI) An IBM API
subset of HLLAPI.
- EOT: See End of Transmission
- EPROM: See Erasable Programmable Read-Only Memory
Room: A room that serves the space needs for larger telecommunications
equipment. Note: These are often special purpose rooms. Equipment rooms are
connected to the backbone facility.
Programmable Read-Only Memory: (EPROM) A nonvolatile semiconductor PROM
that can be erased by exposing it to intense ultraviolet light for
- Erasable Storage: A storage device whose contents can be
modified, (e.g. Random Access Memory, or RAM), as contrasted with read-only
storage (e.g. Read-Only Memory, or ROM).
- Error: A term used to
describe signals with a rate or value below the accepted norms. An error may be
caused by mutilation of bits, loss of bits or character, or improper DLC (Data
Link Control) procedure.
- Error Condition: The discrepancy between the
sent data & the received data. Error condition may be caused by mutilation of
bits, loss of bits or characters, or improper use of DLC procedure.
Rate: A measure of data integrity, expressed as a fraction of corrupted
bits over transmission bits per second.
- ESCON: IBM’s “Planning for
Enterprise Systems Connection Links” provides information on fiber optic cable
types & environment for ESCON capable devices. ESCON is intended for use in a
mainframe environment rather than for local area networking or
- ESDI: See Enhanced Small Device
- Establishment Procedure: The ASCII term for initial
handshaking, a sequence in data transfer. During Establishment Procedure, the
two communicating DTE's may exchange identities & confirm that they are able to
- ETB: See End of Transmission
- Ethernet: A 10 Mbps network standard using CSMA/CD access.
It was developed by Xerox, DEC & Intel.
- EtherTalk: AppleTalk protocol
governing Ethernet transmissions. Also the Apple computer Ethernet adapter &
- Ethertype: A 2 byte code indicating protocol type in an
Ethernet packet. ETX: (End of Text) A control character in the DLG. ETX
indicates the end of text information in a block.
- Even Parity: A
"dumb" terminal data-verification method in which each character must have an
even number of "1" bits.
- Expanded Memory: A PC's address memory
(above 1 Meg)
- EXT: End of Text
Binary Coded Decimal Interchange Code: (EBCDIC) An 8 bit character code
used primarily in IBM equipment; the code provides for 256 different bit
patterns; compare with ASCII.
- Extended Industry
Standard Architecture: (EISA) A 32 bit adaptation of the 8 & 16 bit buses
originally developed by IBM & now standard in almost all PC's that use Intel
8086, 80286 & 80386 microprocessors. The EISA bus is joint development of
COMPAQ & other PC manufactures.
- Extended Memory: A PC's address
memory (640K to 1 Meg.)
- Exterior Gateway Protocol:
(EGP) A protocol used to advertise the OP address of one networks system to
another. Each individual system must use EGP to advertise their reachability by
the routing system.
- External Storage Controller: A sub-unit in a
computer or attached to a computer that manages the movement of data between
the computer & the external storage device(s), such as, disk drives & tape