E - 1. Symbol for voltage. Usually used to represent direct voltage or the effective (root-mean-square) value of an alternating voltage. 2. A UL cable type. Elevator lighting and control cable.
EAC - Electronic Access Control.
EAP - Extensible Authentication Protocol.
Earth - British terminology for zero-reference ground.
Earthing conductor - A conductor that goes from a known earth ground to a device to be grounded.
Eccentricity - Like concentricity, a measure of the center of a conductor’s location with respect to the circular cross section of the insulation. Expressed as a percentage of displacement of one circle within the other.
Echo - 1. A faint return of the transmitted signal to the originating modem when a signal is related by a communications satellite. 2. The interference caused when a modem receives its own signal, experienced when two 9,600-bps modems communicate, each using most of the available bandwidth.
Echo canceller - A device that digitally compensates for echo signals that appear on telecommunications circuits.
Echo suppressor - A device used by telcos or PTTs that blocks the receive side of the line during the time that the transmit side is in use.
Echoplex - A method of checking data integrity by returning characters to the sending station for verification of data integrity.
Ecma International (European association for standardizing information and communications systems) - Before 1994, Ecma was known as the European Computer Manufacturers Association (ECMA). After 1994, Ecma was implemented as a trademark to represent the historical aspect of the organization. Ecma is an industry association dedicated to the standardization of information and communications technology and consumer electronics.
ECTFE - (Halar) An Ausimont Co. trademark for ethylene chlorotrifluoro ethylene. Used as an insulation or jacketing material.
ED (ending delimiter) - In the FDDI frame and token-format blocks, this contains non-data symbols to indicate the end of the frame. The delimiter is eight bits long for a token (two consecutive T symbols) and four bits long (a single T symbol) for all other frames.
Eddy current - An electric current induced in a conductor by a varying magnetic field.
EDFA - Erbium doped fiber amplifier (fiber amplifier).
EEPROM (electrically erasable programmable read only memory) - An EPROM that can be cleared with electrical signals rather than the traditional ultraviolet light.
EFM (Ethernet in the First Mile) - There is a standard IEEE 802.3ah.
EFS (end of frame sequence) - In the FDDI frame and token-format blocks, this consists of ED (encoding delimiter) and FS 9 (frame status) fields, which ensure a clear function occurs close to each frame.
EI (electronic iris) - Automatically changes a CCD camera’s shutter to mimic auto iris control, allowing fixed or manual iris lenses to be used in a range of areas that used to require an auto iris lens.
EI - The European standard for high-speed data transmission at 2.048 Mbps. Thirty-two 64 kbps channels are provided.
EIA crossover cable - A seven-wire cable used to change a DCE to DTE. It is terminated on both ends with a male connector and serves both the AIM8 and AIM4 circuits.
EIA RS-232-C - A standard, defined by the Electronics Industries Association, describing the electrical, mechanical and functional characteristics of the connections between devices exchanging data in serial binary form.
EIA RS-232-C port - A 25-pin male or female connector compatible with RS-232-C signals and cable.
EIA signal - A digital signal having a number of characteristics (in time duration, voltage and current) defined by the Electronics Industries Association as standards for data communication.
Elastomer - Any material that will return to its original dimensions after being stretched or distorted.
Electromagnet - A device consisting of a ferromagnetic core and a coil that produces appreciable magnetic effects only when an electric current exists in the coil.
Electromagnetic coupling - The transfer of energy by means of a varying magnetic field. inductive coupling.
Electromagnetic - Referring to the combined electric and magnetic fields caused by electron motion through conductors.
Electromechanical cables - Dual purpose composite cables made up of support strands capable of supporting predetermined loads together with communication, coaxial or power as integral members of a finished cable.
Electromotive Force (EMF) - Pressure or voltage. The force that causes current to flow in a circuit.
Electron volt - A measure of the energy gained by an electron passing through an n electric field produced by one volt.
Electron - An elementary particle containing the smallest negative electric charge; Mass=9.1 x 1,031; Charge=0.16 attocoulom; Diameter=1 femtometer.
Electronic shuttering - Electronic shuttering is the ability of the camera to compensate for moderate light changes in indoor applications without the use of auto iris lenses.
Electronic wire and cable - Wire or cable used in electronic applications.
Electronic wire and cable - Wire or cable used in electronic applications.
Electro-osmosis - The movement of fluids through dielectrics because of electric current.
Electrostatic coupling - The transfer of energy by means of a varying electrostatic field. Capacitive coupling.
Electrostatic coupling - The transfer of energy by means of a varying electrostatic field; capacitive coupling.
Electrostatic discharge (ESD) - An instantaneous flow of an electrical charge on a nonconductor through a conductor to ground.
Electrostatic - Pertaining to static electricity or electricity at rest. For example, an electric charge.
Electrostatic - Pertaining to static electricity, or electricity at rest. For example, a static electric charge.
Electro-tinned - Electrolytic process of tinning wire using pure tin.
Elexar - Shell trademark for a thermoplastic Elastomer (TPE).
Elfext (equal level far-end crosstalk) - A measure of the unwanted signal coupling from a transmitter at the near-end into a neighboring pair measured at the far-end relative to the received signal measured on that same pair. ELFEXT is FEXT-adjusted to discount attenuation.
Elongation - The fractional increase in the length of a material stressed in tension.
EMA (electrical moisture absorption) - A water tank test during which the sample cables are subjected to voltage while the water is maintained at rated temperature; the immersion time is long, with the object being to accelerate failure due to moisture in the insulation; simulates buried cable.
EMB - Effective modal bandwidth.
Embossing - Identification by means of thermal indentation that leaves raised lettering on the sheath material of cable.
Emergency overload - A situation in which larger than normal currents are carried through a cable or wire for a limited period of time.
EMF (electromotive force) - See VOLTAGE.
EMI (electromagnetic interference) - External signals that disrupt the data being transmitted on the local area network or electronic device being operated. Typically, these external signals emanate from universal motors with brushes, fluorescent lights, personal computers, printers or other devices including copy machines, etc. The Federal Communications Commission (FCC) regulates this emission area.
EMI/RFI filter - Circuit or device containing series inductive (load-bearing) and parallel capacitive (non-load-bearing) components that provide a low-impedance path around the protected circuit for high-frequency noise. Filters and surge suppressors when used together act synergistically.
Endosmosis - The penetration of water into a cable by osmosis; aggravated and accelerated by DC voltage on the cable.
Ends - In braiding, the number of essentially parallel wires or threads on a carrier.
Energize - To apply voltage to a circuit or device in order to activate it.
Entrance facility, telecommunications - An entrance to a building for both public and private network service cables (including antennae) including the entrance point at the building wall and continuing to the entrance room or space.
Environment - 1. The universe within which a system must operate 2. All the elements over which the designer has no control and that affect a system or its puts and outputs.
EO - A UL cable type. Elevator lighting and control cable with thermoset insulation.
EOT (end of transmission character) - A transmission control character used to indicate the end of transmission, which may include one or more texts and any associated message headings.
EP, EPR, EPM, and EPFM - Designations for synthetic rubber based upon ethylene-propylene hydrocarbon.
EPA (Environmental Protection Agency) - The federal regulatory agency responsible for keeping and improving the quality of our living environment – mainly air and water.
EPDM (ethylene propylene diene monomer) - A rubber thermoset material with good insulating properties.
EPON - Ethernet passive optical network.
EPR - Ethylene propylene rubber.
EPROM (erasable programmable read-only memory) - A nonvolatile semiconductor PROM that can have three current contents cleared (usually through exposure ultraviolet light) and then accept new contents for storage.
Equalization - Equalization is achieved by circuitry that compensates for the differences in attenuation at different frequencies.
Equalizer - A device used by modems to compensate for distortions caused by telephone line conditions.
Equilay conductor - A conductor constructed with a central wire surrounded by more than one layer of helically-laid wires, all layers having a common length of lay, direction of lay being reversed in successive layers.
Equilay conductor - See CONCENTRIC-LAY CONDUCTOR.
Equipment grounding conductor - A conductor used to connect noncurrent-carrying metal enclosures of electrical equipment to the system ground.
Equipment room - The room in which voice and data common equipment are housed, protected and maintained, and where circuit administration is performed using the trunk and distribution cross-connects.
Equipment wiring subsystem - The part of a premises distribution system that includes the cable and distribution in an equipment room and that interconnects system-common equipment, other associated equipment and cross-connects.
ER rated - Exposed Run. An optional UL rating on UL Listed cable Types TC, ITC and PLTC that meet the same crush and impact requirements as metal clad (Type MC) cables. Formerly called Open Wiring rated. Permits exposed runs between cable tray and utilization equipment.
Error detection - A hardware or software protocol determining when a group of incoming data has an error. If one is detected, the receiving modem orders the transmitting modem to resend the data group that contains the error.
Error rate - A measure of data integrity, given as the fraction of bits which are flawed. Often expressed as a negative power of 10, as in 10-6 (a rate of one error in every one million bits).
ESCON - IBM Enterprise Systems Connection. A highly flexible channel interconnection environment with extended distance range, it combines technology and architecture including optical fiber cabling, dynamic connectivity, interconnectivity with other networks and input/output (I/O) architecture that exploits optical fiber.
ESF - Extended super frame format.
ET - A UL cable type. Elevator lighting and control cable with thermoplastic insulation, three braids, flame-retardant and moisture-retardant finish. May have steel supporting strand in the center, 300 V.
Etched wire - A process applied to Teflon wire in which the wire is passed through a sodium bath to create a rough surface to allow epoxy resin to bond to the Teflon.
ETFE - (Tefzel) DuPont trademark for ethylene tetrafluoroethylene.
Ethernet - Ethernet is a network standard of communication using either coaxial or twisted-pair cable. The most widely used in LAN communications, Ethernet typically runs at 10 megabytes per second, though newer systems use 100 Mbps or 10 Gbps.
ETL - Electrical testing laboratory.
ETPC - Abbreviation for electrolytic tough pitch copper. It has a minimum conductivity of 99.9 percent.
ETPR (expanded thermal plastic rubber) - ETPR is often used as a filling compound in OSP cable.
EVA - Ethylene vinyl acetate. A polymer often used for the jacket in low smoke, zero halogen, flame retardant cables. Often referred to as a polyolefin.
Exchange - A unit established by a common carrier for the administration of communications services in a specified geographical area such as a city. It consists of one or more central offices together with the equipment used in providing the communications services. Frequently used as a synonym for central office.
Excitation losses - Losses in a transformer or electrical device because of voltage.
Exit angle - The angle between the output radiation vectors and the axis of the fiber or fiber bundle.
Expanded diameter - Diameter of shrink tubing as supplied. When heated the tubing will shrink to its extruded diameter.
Explicit access - In LAN technology, a shared access method that allows stations to use the transmission medium individually for a specific time period; every station is guaranteed a turn, but every station must also wait for its turn. Contrast with CONTENDED ACCESS.
Extension tube - Kit consisting of various size spacers that are used between the lens and the camera to reduce the lens MOD. Generally used for very close-up applications. Not recommended for zoom lenses due to loss of tracking.
External timing - Use of a timing source that is external to the transmission system. This timing source synchronizes the transit and receives circuits with a given facility.
External wiring - Electronic wiring that interconnects subsystems within the system.
Extruded cable - Cable that is insulated by applying insulation material in a continuous extrusion process.
Extrusion - A method of applying insulation to a conductor or jacketing to a cable. The process is continuous and uses rubber, neoprene or a variety of plastic compounds.