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Jan 30, 2009

Fiber Optic :: Glossary :: G - I

Gap loss - The optical power loss caused by a space between axially aligned fiber optic cables. For waveguide-to-waveguide coupling, it is commonly called longitudinal offset loss.

GBPS - Giga Bits Per Second - 1 Billion Bits Per Second.

GHz. - Giga Hertz, 1 Billion Hz.

GI - Graded indexes.

GI-POF - Graded index plastic fiber optic cable.

GOF - Glass Optical Fiber.

Graded index fiber - A fiber optic cable where the core has a non-uniform index of refraction. The core is composed of concentric rings of glass where the refractive indices decrease from the center axis. The purpose is to reduce modal dispersion and thereby decrease fiber bandwidth.

Graded index profile - Any refractive index profile that varies with radius in the core.

GRIN - Graded indexes.

Ground loop noise - Noise that results when equipment is grounded at ground points having different potentials. This creates an unintended current path. The dielectric of fiber optic cables provides electrical isolation that eliminates ground loops.

Hard clad silica - A fiber optic cable with a hard plastic cladding surrounding a silica glass core.

Hertz - A unit of frequency equal to 1 cycle per second.

Hot plate - Heat source used to produce a mirror finish on the end of a plastic fiber optic cable.

HSPN - High Speed Plastic Network- a program funded by the US Government to promote plastic fiber optic cabling components and applications.

Hybrid adapter - Device that connects various connector types.

Hybrid cable - A cable composed of both a fiber optic cable and electrical conductors. Synonym for composite cable.

IDP - Integrated detector/amplifier.

IEC - International Electrical Commission.

IEEE - Institute of Electrical and Electronics Engineers.

Incident angle - The angle between an incident ray and a line perpendicular to an optical surface.

Index matching material - A material used at an optical interconnection. It has a refractive index close to that of the fiber optic cable core and is used to reduce Fresnel reflections.

Index of refraction - The ratio of the speed of light in a vacuum to the speed of light in a material. The symbol for it is 'n'.

Index profile - A graded-index fiber optic cable. In it the refractive index at a point varies with the distance of the point from the cylindrical axis i.e. n varies with the radius.

Infrared - The designation for electromagnetic waves at wavelengths between the visible part of the spectrum (approximately 750 nm) and the microwave band (approximately 30 mm).

ILD - Injection Laser Diode.

Insertion loss - The loss in the power of a signal that results from inserting a passive component into a previously continuous path. Examples of such passive devices are connectors, inline star couplers and splices.

Integrated detector/amplifier - A detector package containing a pin photodiode and a transimpedence amplifier.

Interface - The debarkation point or location on a data device where data comes out of or goes into the device. Examples are the RS-232 interface and the Mouse-PC interface.

Intrinsic losses - Loss caused by fiber optic cable parameter mismatches when 2 non-identical cables are joined. Examples of such parameters are core dimensions and index profiles.

IR - Infrared.

ISDN - Integrated Services Digital Network. A TELCO offering to allow computers to communicate through the telephone Wide Area Network at speeds up to 128 KBPS.

ISO - International Standards Organization. This is an independent international body formed to define standards for multi-vendor network communications. Its 7 layer Open Systems (OSI) reference model defines the protocol layers of network architectures which vendors should account for in their product offerings.

Isolation - Also referred to as far end crosstalk or far end isolation. Predominantly used in reference to WDM products. It is a measure of light at an undesired wavelength at any given port.

Jan 29, 2009

Fiber Optic :: Glossary :: F

Fall time - The time required for the trailing edge of a pulse to fall from 90% to 10% of its amplitude. The time required for a component to produce such a result. Turn off time. Sometimes measured between the 80% and 20% points.

Fan Out cable - Same as a Break Out cable. This is a multiple fiber optic cables constructed in the tight buffered design. It is designed for ease of connectorization and rugged applications for intra-building and inter-building requirements.

FC - A connector type. It is utilized for single-mode fiber optic cable. It offers extremely precise positioning of the single-mode fiber optic cable with respect to the emitter and detector. It features a position locatable notch and a threaded receptacle. Once installed, the position is maintained with absolute accuracy.

FC/PC - A connector type. It is utilized for single mode cable. It offers extremely precise positioning of the single mode cable with respect to the emitter and detector. It features a position locatable notch and a threaded receptacle. Once installed the position is maintained with absolute accuracy.

FDD I - Fiber Distributed Data Interface. A very high-speed local area networking architecture based upon fiber optic cable as the transmission medium. Many FDDI features were incorporated into Fast Ethernet-100Base-T. FDDI has its own special type of connector.

Ferrul - A component of a connector that holds a fiber optic cable in place and aids in its alignment. It is usually cylindrical in shape with a hold through the center.

Fiber - Thin filament of glass. An optical waveguide consisting of a core and a cladding which is capable of carrying information in the form of light.

Fiber bandwidth - The lowest frequency at which the magnitude of the fiber transfer function decreases to a specified fraction of the zero frequency value. Often the specified value is ½ of the value of the transfer function at zero frequency.

Fiber bundle - An assembly of unbuffered fiber optic cables. It is usually employed as a single transmission channel. This is in contrast to multi-fiber cables, which contain optically and mechanically isolated fiber optic cables, each of which provides a separate channel. Fiber bundles, which are used only to transmit light as in fiber optic data communications, are flexible and unaligned. On the other hand, fiber bundles which are used to transmit images may be flexible or rigid, but must contain aligned fibers.

Fiber channel - An industry standard specification for computer channel communications over a fiber optic cable. It offers data transmission speeds from 132 MBPS to 1,062 MBPS and transmission distances for 1 to 10 km

Fiber loss - The attenuation (deterioration) of the light signal in transmission through a fiber optic cable.

Fiber Distributed Data Interface network - A token passing ring network designed specifically for fiber optic cable and featuring dual counter-rotating rings and 100 MBPS operation.

Fiber optic interrepeater link - Standard defining a fiber optic cable link between 2 repeaters in an IEEE 802.3 network.

Fiber optic link - Any transmission channel using a fiber optic cable as the transmission medium to connect 2 end terminals or to be connected in series with other channels.

Fiber optics - Light transmission through optical fibers for communication or signaling.

Fiber Optic Test Procedure (FOTP) - Standards developed and published by the Electronic Industries Association (EIA) under the EIA's RS-455 series of standards.

Fiber optic waveguide - A relatively long strand of transparent substance, usually glass, capable of conducting an electromagnetic wave of optical wavelength (visible or near visible region of the frequency spectrum) with some ability to confine longitudinally directed, or near longitudinally directed, lightwaves to its interior by means of internal reflection. The fiber optic waveguide may be homogeneous or radically inhomogeneous with step or graded changes in its refractive index. The indices are lower at the outer regions and the core is thus of an increased refractive index.

FITL - Fiber in the loop.

FM - Frequency modulation.

FO7 - Plastic fiber optic cable connector standardized in Japan.

FOIRL - Fiber optic interrepeater link.

FOTS - Fiber optic transmission system.

F4B/5B Encoding - A signal modulation scheme in which groups of 4 bits are encoded and transmitted in 5 bits in order to guarantee that no more than 3 consecutive zeros ever occur. It is used in FDDI.

FP-LD - Fabry-Perot laser diode.

Frequency modulation - A transmission technique in which the frequency of a carrier is varied in sympathy with the information being communicated.

Fresnel reflection - The reflection that occurs at the planar junction of 2 materials having different refractive indices. Fresnel reflection is not a function of the angle of incidence.

Fresnel reflection loss - Loss of optical power due to Fresnel reflections.

Fundamental mode - The lowest order propagation mode of a waveguide.

Fused coupler - A method of making a multi-mode or single-mode coupler by wrapping fiber optic cables together, heating them and pulling them to form a central unified mass. By doing this light on any input fiber optic cable is coupled to all out put fiber optic cables.

Fusion splicing - A permanent joint accomplished by the application of localized heat sufficient to fuse or melt the ends of the fiber optic cable. This process forms a single continuous fiber optic cable.

Fusion splice - A joining of 2 fiber optic cables by physically fusing through heat the 2 fiber optic cable ends.

FWHM - Full width at half maximum. This is used to describe the width of a spectral emission.

Fiber Optic :: Glossary :: E

EDFA - Erbium-doped fiber amplifier.

EIA - Electronics Industries Association. A standards association that publishes test procedures.

8B/10B encoding - A signal modulation scheme in which either 4 bits are encoded into a 5-bit word or eight bits are encoded into a 10-bit word. This scheme ensures that too many consecutive zeros do not occur. It is used in ESCON and Fiber Channel.

802.3 network - A 10 MBPS CSMA/CD bus based LAN; commonly called Ethernet.

802.5 network - A token passing ring network operating at 4 or 16 MBPS.

EMC - Electromagnetic compatibility

EMD - Equilibrium mode distribution.

EMI - Electromagnetic interference. It is any electrical or electromagnetic interference that causes an undesirable response, degradation or failure in electronic equipment. Fiber optic cables neither emits nor receives EMI.

Emitter - Term used for a light source.

Encoding - A scheme to represent digital ones and zeros through combining high and low voltage states.

End separation - The distance between the ends of 2 joined fiber optic cables. End separation causes an extrinsic loss that depends on the joining hardware and method.

End to End Loss - The optical loss on an installed fiber optic cable data link path. This loss consists of the loss due to the fiber optic cable, splices and connectors.

Equilibrium mode distribution - The steady modal state of a multi-mode fiber optic cable in which the relative power distribution among the modes is independent of the fiber optic cable length.

Erbium-doped fiber amplifier - A type of fiber optic cable that amplifies 1550 nm optical signals when pumped with a 980-1480 nm light source.

ESCON - An IBM channel control system based on fiber optic.

ESKA - Trade mark of plastic fiber optic cable manufactured by Mitsubishi Rayon Corp.

ESKA GIGA - Graded index plastic fiber optic cable manufactured by Mitsubishi Rayon Corp.

ESKA MEGA - Trade mark of plastic fiber optic cable manufactured by Mitsubishi Rayon Corp.

Excess loss - There are 2 contexts in which it is used. First, in a fiber optic coupler it is the optical loss from that portion of light that does not emerge from the nominally operational ports of the device. Secondly, it is the ratio of the total output power of a passive component to the input power.

Extrinsic Losses - Signal loss in transmission down fiber optic cable caused by imperfect alignment of fiber optic cables joined by a connector or splice. Contributors to this loss include angular misalignment, axial misalignment, end separation and end finish - any imperfect joining caused by connector or splice.

Jan 27, 2009

Fiber Optic :: Glossary :: D

Dark current - The thermally induced current that exists in a photodiode in the absence of incident optical power.

Data link - Transmitter with Modulator, Transmission medium and Demodulator with Receiver that transmits data between 2 points. When the Transmission medium is a fiber optic cable the data link is a fiber optic data link.

Data rate - Also Data Transmission Rate. The number of bits of information sent per second in a data communications transmission system. It is generally expressed in Bits Per Second, BPS. This may or may not be equal to the Baud rate.

dB - Decibel, a measure of loss or equivalently attenuation. It is computed as a standard logarithmic unit for the ratio of 2 powers, voltages or currents. In fiber optics the ratio is power and defined by: dB = 10 Log10 (P1/P2).

dB loss budget - The amount of light available to overcome the attenuation in the fiber optic data link and still maintain BER (or equivalent) performance specifications.

dBm - Decibels below 1 mW.

dBm - Decibels below 1mW.

Demultiplex - Separation of channels which has been multiplexed in order to share a common transmission medium. With respect to a fiber optic cable medium it is the process of separating optical channels.

Detector - A device that generates an electrical signal when illuminated by light. The electrical current is dependent upon the amount of light received. Common detectors encountered in fiber optic data communications are photodiodes, photodarlingtons and phototransistors.

D4 - A connector type. It is very similar to the FC connector with its threaded coupling, tunable keying and PC end finish. The main difference is its 2.0-mm diameter ferrule. Designed originally by the Nippon Electric Corp.

Diameter-mismatch loss - The loss of power at a joint that occurs when the transmitting half has a diameter greater than the diameter of the receiving half. The loss occurs when coupling light from a source to a fiber optic cable, from a fiber optic cable to another fiber optic cable or from a fiber optic cable to a detector.

Diamond connector - A type of connector.

Dichroic filter - An optical filter that transmits light selectively according to wavelength.

Dielectric - Non-metallic and therefore non-conductive. Glass fiber optic cable is therefore considered dielectric. A dielectric cable contains no metallic components.

Diffraction grating - An array of fine, parallel, equally spaced reflecting or transmitting lines. These lines mutually enhance the effects of diffraction to concentrate the diffracted light in a few directions. These directions are determined by the spacing of the lines and by the wavelength of the light.

Digital - A data format that uses a discrete, countable and finite number of levels to transmit information. Binary is a special case of this corresponding to 2 levels.

DIN 47256 - A connector type.

Directivity - This is also referred to as near end crosstalk. It is the amount of power observed at a given input port with respect to an initial input power.

Dispersion - A general term for those phenomena that cause a broadening or spreading of light as it propagates down a fiber optic cable. This is the major cause of bandwidth limitations with fiber optic cable. There are 3 types of dispersion- modal, material and waveguide. Differential optical path lengths in multi-mode fiber optic cables cause modal dispersion. Material dispersion is caused by a differential delay of various wavelengths of light in a waveguide material. Waveguide dispersion is caused by light travelling in both the core and cladding materials in single-mode fiber optic cables.

Distortion-limited operation - Generally synonymous with bandwidth limited operation.

Dopan - Materials added to a core of a fiber optic cable in order to change its characteristics.

Drawing - The manufacturing process by which fiber optic cable is pulled from preforms.

Duplex cable - A 2 fiber cable suitable for duplex (2 way) transmission.

Duplex operation - Transmission on a data link in both directions. Half duplex refers to such transmission, but in a time-shared mode- only one direction can transmit at a time. With full duplex there can be transmission in both direction simultaneously.

Duty cycle - In digital transmission, the ratio of high levels to low levels or the ratio of on time - signal present - to total time - as averaged over many bit or Baud intervals.

Jan 26, 2009

Fiber Optic :: Glossary :: C

Cable - Alternate name for fiber optic cable. An assembly of optical fibers (the glass or plastic basic waveguide) and other material providing mechanical and environmental protection and optical insulation of the inner optical waveguide.

Cable assembly - Fiber optic cable that has connectors installed on one or both ends. General use of these cable assemblies includes the interconnection of multi-mode and single-mode fiber optic cable systems and opto-electronic equipment. If connectors are attached to only one end of the cable, it is known as a pigtail. If connectors are attached to both ends, it is known as a jumper.

Cable bend radius - During installation this infers that the cable is experiencing a tensile load. Free bend infers a lower allowable bend radius since it is at a condition of no load.

Carrier Sense Multiple Access With Collision Detection CSMA/CD - A technique employed in Ethernet based LANs to control the transmission channel. It assures that there is no conflict between terminals that wish to transmit.

Center wavelength - The wavelength of an optical source that might be considered its middle. One measure of this is the average of the 2 wavelengths corresponding to the Full Width Half Maximum- FWHM.

Central member - The center component of a fiber optic cable. It serves as an anti-buckling element to resist temperature-induced stresses. Sometimes serves as a strength element. The central member is composed of steel; fiberglass or glass reinforced plastic.

Central office - CO. The places where communications common carriers terminate customer lines and locate switching equipment that interconnects those lines. It is the lowest hierarchical level of a TELCO backbone network. It is from the Central office level that local loops go out to end-user customer premises equipment.

Centro-symmetrical Reflective Optics - An optical technique in which a concave mirror is used to control coupling of light from 1 fiber optic cable to another.

Channel - A communications path derived from a specific transmission medium, as for example fiber optic cables. The channel supports the end-to-end communications of an information source and destination. Besides the transmission medium a channel needs to have a transmitter/receiver (transceiver) and a modulator/demodulator (modem). By multiplexing, several channels can share the same specific transmission medium. Channel is synonymous with link. The term channel is usually employed within the context of multiplexing- but not always.

Chromatic bandwidth - The inverse of the Chromatic Dispersion.

Chromatic dispersion - The speed of an optical pulse travelling down a fiber optic cable changes if the wavelength changes. However, any practical light source has a spectral width that is, has components at a number of different wavelengths. This results in a pulse broadening - the time width of pulse broadens as it propagates down a fiber optic cable. This effect is called chromatic dispersion. It can be calculated experimentally by measuring the travel time down a fiber optic cable of light at different wavelengths.

Cladding - A low refractive index glass or plastic that surrounds the core of the fiber optic cable. Optical cladding promotes total internal reflection for the propagation of light in fiber. The cladding steers light to the core.

Cladding modes - A mode that is confined to the cladding. Basically, a light ray that propagates down the cladding. Attenuation is very high in the cladding. Consequently, a cladding mode is eliminated after a few meters.

Cleaving - The controlled breaking of a fiber so that its end surface is smooth.

Club Des Fibres Optiques Plastiques - Club formed in France to promote Plastic Optical Fiber (POF) for a variety of applications.

Coating - A material put on a fiber optic cable during the drawing process to protect if from the environment.

Coherent light or light waves - This is light of which all parameters are predictable and correlated at any point into time or space, particularly over an area perpendicular to the direction of propagation or over time at a particular point in space. Simply, coherent light usually refers to the phenomenon relating to the existence of a correlation between the phases of the corresponding components of 2 light waves or to the values of the phase of a given component at 2 instants in time or 2 points in space. Coherent light does not occur naturally in the Universe. It can only be generated a laser.

Concentrator - A multi-port repeater.

Conduit - Pipe or tubing through which cables can be pulled or housed.

Connector - A mechanical device mounted on the end of a fiber optic cable, light source, receiver or housing that mates to a similar device. It allows light to be coupled, optically, into and out of a fiber optic cable. A connector allows a fiber optic cable to be connected or disconnected repeatedly from a device. Commonly used connectors include FC/PC, Biconic, SC, ST, D4, and SMA 905 or 906.

Connector insertion loss - See Insertion Loss.

Connector-induced fiber loss - That part of the Conductor Insertion Loss, expressed in dB, due to impurities or structural changes to the fiber optic cable by termination or handling with the connector.

Core - The central, light carrying, part of a fiber optic cable. It has an index of refraction higher than that of the surrounding cladding.

Core eccentricity - A measure of the displacement of the center of the core relative to the cladding center.

Coupler - It is used in 2 contexts. First, it is a passive device that distributes optical power among 2 or more ports and this can be in different ratios. Secondly, it is a multi-pod device used to distribute optical power.

Coupling efficiency - The efficiency of optical power transfer between 2 components.

Coupling losses - The power loss suffered when coupling light from one optical device to another. There are intrinsic losses (non-ideal fiber parameters) and extrinsic losses (mechanical effects).

Coupling ratio - The percentage of light transferred to a receiving output port with respect to the total power of all output ports.

CPE - Customer Premises Equipment.

Critical angle - The greatest angle of incidence for which a wave propagating in a homogeneous medium of relatively high refractive index strikes an interface with a medium having a lower refractive index and for which refraction in just possible. With respect to fiber optic cabling the critical angle is therefore the smallest angle at which a light ray will be totally reflected within the fiber and thereby guided down the fiber - total internal reflection.

Crosstalk - The pickup in one particular fiber optic cable of unwanted light from another fiber optic cable.

CSMA/CD - Carrier Sense Multiple Access with Collision Detection.
CSR - Centro symmetrical reflective optics.

Cutback - A method for measuring the attenuation or bandwidth of a fiber optic cable by first measuring the full length and then cutting back and measuring, again, the fiber optic cable at a shorter length.

Cut off wavelength - For a single mode fiber optic cable it is the wavelength above which the fiber optic cable exhibits single mode operation.

Jan 25, 2009

Fiber Optic :: Glossary :: B

Backscattering - The return of a portion of scattered light to the input end of a fiber optic cable. It is the scattering of light in the direction opposite to its original direction of propagation.

Balanced - Signaling code with an equal number of high and low states.

Bandpass - A range of wavelengths over which a component will meet specifications.

Bandwidth - The information capacity of a fiber optic cable. Precisely it is usually measured in GHz (1 Billion Hz). Occasionally it is idiomatically discussed in terms of the data transmission rate- the BPS- the actual GHz bandwidth can support. In some contexts it is expressed as MHz-km and denotes the analog bandwidth capability of digital transitions per second that a fiber optic cable can sustain over a 1-km distance. Occasionally the bandwidth of a light source is referred to. This is the width of the spectrum emitted.

Bandwidth-limited operation - The condition in a fiber optic cable based communications link when bandwidth, rather than received signal power, limits performance. This condition is reached when the signal becomes distorted, principally by dispersion, beyond specified limits.

Baseband - A method of communication in which a signal is transmitted at its original frequency rather than being impressed upon a carrier frequency.

Baud - A unit of data transmission signaling speed - data transmission rate - equal to the number of signal symbols per second. With binary modulation systems this is the same as the data transmission rate in Bits Per Second. However, it is different with non-binary modulation systems.

Beam splitter - An optical device, such as a partially reflecting mirror, for dividing an optical beam in 2 or more separate beams. It can be used in a fiber optic cable data link as a directional coupler.

Bend loss - A+ form of increased attenuation caused by allowing high order modes to radiate from the walls of a fiber optic cable. There are 2 common types of bend losses. The first type results when the fiber optic cable is curved through a restrictive radius or curvature. The second type is generally referred to as microbends. It is caused by small distortions of the fiber optic cable imposed by externally induced perturbations as, for example, slip shod cabling techniques.

Bend radius - Radius a fiber optic cable can bend before the risk of breakage or increase in attenuation. Also referred to as cable bend radius.

BER - Bit Error Rate. This is the probability that a transmitted bit is demodulated in error at the destination receiver.

Biconic - A connector type which has a taper sleeve which would be fixed to the fiber optic cable. When this plug was inserted into its receptacle the tapered end was a means for locating the fiber optic cable in the proper position. With this connector cap, fit over the ferrules, rest against guided rings and screw onto the threaded sleeve to secure the connection. This was one of the earliest connectors used in fiber optic systems but is in little use at present.

Bit - A binary digit which is generally either '0' or '1.' It is the smallest representation of information in a communications and/or computing system.

Bit rate - The number of bits of data transmitted per second over a communications link. This usually represented as BPS with KBPS standing for kilo bits per second (1000 BPS) and MBPS standing for mega bits per second (million BPS) and GBPS standing for giga bits per second (billion BPS) etc.

Break Out cable - Same as a Fan Out cable. This is a multiple fiber optic cables constructed in the tight buffered design. It is designed for ease of connectorization and rugged applications for intra-building and inter-building requirements.

Broadband - A method of communication in which the signal is transmitted by being impressed on a higher frequency carrier. Also the ability of a communications system to carry a multitude of signals simultaneously. In data transmission is denotes transmission facilities capable of handling frequencies greater than those for high-grade voice communications. The higher frequency allows the carrying of several simultaneous channels. Broadband infers the use of a carrier signal rather than direct modulation, baseband.

Buffer - A protective layer over the fiber optic cable, such as a coating, an inner jacket, or a hard tube. The primary buffer, next to the cladding, is 250 mm in diameter. A secondary buffer of 900 mm is used on indoor cables.

Buffer coating - A protective layer, such as an acrylic polymer, applied over the fiber optic cable cladding.

Buffered fiber - Fiber optic cable protected with an additional material, usually hytrel or nylon, to provide ease in handling, connectorization and increased tensile strength.

Buffering - It is used in 2 contexts. First, it refers to a protective material extruded directly on the fiber optic cable coating to protect it from the environment. Secondly, it refers to extruding a tube around the coated fiber optic cable to allow isolation of the fiber from stresses.

Buffer tube - A hard plastic tube, having an inside diameter several times that of a fiber optic cable, that holds 1 or more fiber optic cables.

Building entrance - Terminal cable entrance point where typically a trunk cable between buildings is terminated and fiber is then distributed through the building.

Bundle - Many individual fiber optic cables within a single jacket or buffer tube. Also, a group of buffered fiber optic cables distinguished in some fashion from another group in the same cable core.

Bus network - A network topology in which all of the terminals are attached to a transmission medium serving as a bus. All other terminals receive all signals transmitted from a terminal connected to the bus.

Bus - Commonly called data bus. The term is used to describe the physical linkage between stations on a network sharing a common communication.

Byte - A unit of 8 bits.

Jan 24, 2009

Fiber Optic :: Glossary :: A

Absorption - Loss of power in a fiber optic cable resulting from conversion of optical power into heat. This is principally caused by impurities, such as transition metals and hydroxyl ions. It is also caused by exposure to nuclear radiation.

Acceptance angle - The half angle of the cone which incident light is totally, internally, reflected by the fiber core. It is the angle over which the core of an optical fiber accepts incoming light, usually measured from the fiber axis. It is equal to the arcsine (NA) where NA is the numerical aperture.

Active area - The area of a detector with greatest response.

AM - Amplitude Modulation.

Amplitude Modulation - A transmission technique in which the amplitude of a carrier is varied in sympathy with the information being communicated.

Analog - A format that uses continuous physical parameters to transmit information. Examples of parameters are voltage amplitude and carrier frequency.

Angle of deviation - In ray optic theory it is the net resultant angular deflection experienced by a light ray after one or more reflections or refraction's. The term is used in reference to prisms with air interfaces. The angle of deviation is the angle between the original incident ray and the emergent ray.

Angle of incidence - In ray optic theory it is the angle between an incident ray and the normal to a reflecting or refracting surface.

Angular misalignment loss - The optical power loss caused by angular deviation from the optimum alignment of source to optical fiber.

Angular tilt - The angle formed by the axes of 2 fibers to be joined. Angular tilt causes an extrinsic loss that depends upon the joining hardware and method.

APD - Avalanche photodiode.

APF - All Plastic Fiber.

Aramid yarn - Strength element used in Siecor cable to provide support and additional protection of the fiber optic cable bundles. Kevlar is a particular brand of Aramid yarn.

ATM - Asynchronous Transfer Mode. This is a new emerging data standard (protocol) that uses many of the same data rates as Fiber Channel and SONET.

Attenuation - In fiber optic cable, attenuation results from absorption, scattering and other radiation losses. It is usually expressed as decibels per kilometer (dB/km) without the negative sign. Calculations and equations involving loss show and use the negative sign.

Attenuation-limited operation - The condition in a fiber optic cable based communications link when operation is limited by the power of the receive signal, rather than by bandwidth or by distortion.

Attenuator - A passive optical component that intentionally reduces the optical power propagating in a fiber optic cable.

Avalanche Photodiode (APD) - A photodiode that exhibits internal amplification of photocurrent. It accomplishes this by avalanche multiplication of carriers in the junction region. As the reverse-bias voltage approaches the breakdown voltage, electron-hole pairs created by absorbed photons acquire sufficient energy to create additional electron-hole pairs when they collide with ions. A multiplication or signal gain is thereby achieved.

Average power - The average level of power in a signal that varies with time.

Axial ray - A light ray that travels along the axis of a fiber optic cable.

Jan 23, 2009

Networking:: Abbreviation Definition :: N - V


O Output

Pa Pascal (for speaker sound pressure measurements)

PBCCH Packet Broadcast Control CHannel

PC Personal Computer

PCL Power Control Level

PDP Packet Data Protocol

PIN Personal Identity Number

PLMN Public Land Mobile Network

PUK Personal Unblocking Key

RF Radio Frequency

RFI Radio Frequency Interference

RI Ring Indicator

RMS Root Mean Square

RTS Request To Send

RX Receive

SIM Subscriber Identification Module

SMA SubMiniature version A RF connector

SMS Short Message Service

SNR Signal-to-Noise Ratio

SPL Sound Pressure Level

SPK SpeaKer


TCP/IP Transmission Control Protocol / Internet Protocol

TDMA Time Division Multiple Access

TU Typical Urban fading profile

TUHigh Typical Urban, High speed fading profile

TX Transmit


USB Universal Serial Bus

VSWR Voltage Stationary Wave Ratio

Jan 22, 2009

Networking:: Abbreviation Definition :: G - M

GCF Global Certification Forum


GPIO General Purpose Input Output

GPRS General Packet Radio Service

GPS Global Positioning System

GSM Global System for Mobile communications

HR Half Rate

I Input

IEC International Electrotechnical Commission

IES Internal Expansion Socket

IESM Internal Expansion Socket Module

IMEI International Mobile Equipment Identification

I/O Input / Output

LED Light Emitting Diode


ME Mobile Equipment

MIC MICrophone

Micro-Fit Family of connectors from Molex


MNP Microcom Networking Protocol

MO Mobile Originated

MS Mobile Station

MT Mobile Terminated

Networking :: Abbreviation Definition :: A - F

AC Alternating Current

ACM Accumulated Call Meter

AT ATtention (prefix for Wireless CPU® commands)


CMOS Complementary Metal Oxide Semiconductor

CS Coding Scheme

CTS Clear To Send

dB Decibel

dBc Decibel relative to the Carrier power

dBi Decibel relative to an Isotropic radiator

dBm Decibel relative to one milliwatt

DC Direct Current

DCD Data Carrier Detect

DCE Data Communication Equipment

DCS Digital Cellular System

DSR Data Set Ready

DTE Data Terminal Equipment

DTMF Dual Tone Multi-Frequency

DTR Data Terminal Ready

EEPROM Electrically Erasable Programmable Read-Only Memory

EFR Enhanced Full Rate

E-GSM Extended GSM

EMC ElectroMagnetic Compatibility

EMI ElectroMagnetic Interference

ESD ElectroStatic Discharges

ETSI European Telecommunications Standards Institute

FIT Series of connectors (micro-FIT)

FR Full Rate

FTA Full Type Approval

Jan 10, 2009

Web Camera - Micro Innovations IC445C VGA Matrix Webcam

350k VGA Matrix

People have dreamed of WebCams years before they were actually made. It is a simple idea: hook a small camera up to your computer, have a friend do the same, and see and hear each other, using a phone line.

WebCams are great new devices that work wonders for families and businesses. Use a WebCam to see and hear a friend who is far away, or to add live video to your Web pages, to take still photos, and even use it for business meetings with videoconferencing software. WebCams are usually small and uncomplicated devices that are fairly easy to set up. Pull it out of the box, install appropriate software and you're ready to get 'webcammed'! Here's some help to get you familiar with what type of WebCam you'll be needing.

What is a WebCam?

A WebCamera is a digital camera that works along with your computer to capture visual images. It's called WebCam or a CyberCam because the Internet offers many possibilities to communicate with this device. It may be used to videoconference and send video emails, among other functions. It can capture images in monochrome (black & white) or color. It can take still pictures or movies. WebCams are small devices, sometimes shaped like a ball, and usually sit on top of a PC desktop monitor. A WebCam differs from a portable digital camera because it only works when it is connected to a computer. Depending on the make and model, it connects to a PC or Mac using a Parallel, Serial, USB, or FireWire port.

WebCam Uses

Everyone from kids to adults have loads of fun with a WebCam. Web cameras are made to be small, handy devices that are relatively easy to set up and handle. Use them at home with your family PC to see family and friends and let them see you. If you have a loved one that lives too far away for you to see every day, shorten the distance with a WebCam. Kids can chat with friends too, and Grandma can finally see the kids, even if they're half way across the globe. At work, use a WebCam to meet with clients anywhere using videoconference software. You can hold virtual meetings and see all participants, while seated at your computer. Create video emails, edit them using software, and send them to friends. Many WebCams allow you to take still photos that you can print-out or post on the web. Some models have ports so you can capture video from a VCR or TV.


Since a WebCam works through a computer, you'll need either a desktop or notebook computer. While many WebCams are designed for use with a Windows PC, there are several models that can work with Apple Macintosh computers. On that computer, you'll need to have an available connection port that is compatible with your WebCam model (USB, Parallel, FireWire, Serial). If you'd like to add audio, you would also need a microphone and computer speakers (or computer headset). Videoconferencing would require a Webcam, a microphone, a speaker or headset, and videoconference software, for each person involved.


WebCam image resolution is measured by the number of pixels (picture elements) in height by the number of pixels in width in a frame (the image the WebCam captures). The higher quantity of pixels yields a higher resolution capability. WebCam resolutions often range from 160 x 160 to 640 x 480. Ideally you want to get as many pixels as you can, but more pixels also mean more graphic information in the data file. When transferring high-resolution pictures over the web, data-transfer time will take longer with high-resolution images. Selecting optimal resolutions may also affect whether you use the WebCam for capturing still images or images with motion.

Frames Per Second

FPS represents Frames per Second. It refers to how many frames are exposed per second. When you are exposing several frames in one second, you have the ability to capture motion. Many WebCams include this feature and usually allow you to control the fps, according to your needs. Two common speed settings are 15 fps and 30 fps. The higher number of frames per second will deliver greater motion integrity. As with resolution, however, the higher number of frames per second adds to the amount of required information and larger files may require longer data-transfer times. As such, many cameras may compromise resolution performance with a higher fps, to keep files manageable.


A WebCam must be connected to your computer in order to capture images. There are various interface ports that a WebCam may use, depending on what ports you have available, and what connectivity the WebCam itself allows. A Parallel connection is the weakest of all ports. Use this port only if you have no other port available. Using the parallel port slows down the computer's processor. One of the more common interface connections is the Universal Serial Bus (USB). This port is one of the easiest and among the fastest of available ports. Most of the WebCams we carry here at J&R come with a USB connection. Though rare, some WebCams are FireWire-enabled. If your computer has a FireWire port, you can connect the WebCam and transfer information at the fastest speeds. If you'd like to attach a WebCam to a notebooks computer, you may also hook it through a PCI or ISA card slot.

WebCam Software

Most WebCams include a manufacturer's bundled software suite in the retail package. There are many optional software titles available that are designed for use with WebCam applications.


Most of the videoconferencing software included with a WebCam will allow you to see and hear people. Hearing other people through your computer will require both an external microphone and speakers. There may be a few WebCam models available that include a microphone or speaker but, generally, they don't.

Web Camera - Microsoft VX-1000 The Total Connection Wired LifeCam

Built-in Microphone / Universal Attachment Base / High-Speed USB 2.0 / Video Effects / Up To 30 Frames Per Second / Flexible 6-Foot Cable / For Windows

Built-in Microphone / Universal Attachment Base / High-Speed USB 2.0 / Video Effects / Up To 30 Frames Per Second / Flexible 6-Foot Cable / For Windows

With simple setup and one-touch calling, the Microsoft LifeCam VX-1000 makes it easier than ever to see and hear your friends and family over the Internet. Hear sounds and voices as if they were in the room with you. See clear live Video images. Experience a new dimension in communication. The LifeCam VX-1000 is optimized for use with Microsoft Windows Live Messenger, so you can share life as it happens. Easily start a video chat by pressing the Windows Live Call Button, and clicking an Online Contact. Crystal-clear video conversation is now possible with more than 200 million contacts in nearly every country in the world.

· See the smiles clearly with 640 × 480 Pixels video and photo resolution

· The built-in Microphone automatically picks up your voice with remarkable clarity

· It’s a snap to attach the LifeCam to any monitor

· Surprise your friends with cool video effects, accessible right from the Windows Live Messenger Window

· LifeCams capture life at 30 frames per second, which means the video images you see are smooth and seamless

· The long, flexible cable gives you more room to move

· System Requirements: Windows XP Pro, Home, Media Center Edition, Tablet PC Edition, Hard Disk Space, 300 MB free, Sound card with speakers or headphones, Pentium II 550 MHz (Pentium 4 1.4 GHz recommended) or higher, 4× speed CD-ROM drive or faster, Display Adapter capable of 800 × 600 resolution or higher, 16-Bit Color depth or higher, 2 MB or more video memory, Keyboard and Microsoft Mouse or compatible pointing device, Auto Update required for one-touch blogging, Internet access required, Internet functions (post to Windows Live Spaces, send in e-mail, video calls), Internet Explorer 6.0 or later Browser Software required for installation, 25 MB Hard-Drive space typically required (users can maintain other default Web browsers after installation), Access to the Internet via an Internet service provider

· Dimensions: Height 2.7 x Width 2.18 x Depth 2.0 inch

Weight: 3.3 ounces

Jan 9, 2009

Web Camera - Logitech 960-000172 QuickCam Ultra Vision Webcam - Macintosh

Up to 960x720 resolution / USB 2.0 Connection / True 1.3-megapixel sensor with RightLight 2 Technology / Mic with RightSound / PC

Up to 960x720 resolution / USB 2.0 Connection / True 1.3-megapixel sensor with RightLight 2 Technology / Mic with RightSound / PC

Logitech 960-000172 QuickCam Ultra Vision SE Webcam is an eye to the outside world through cyberspace. Apart from sending Video and still images of yourself via email, websites, and more, you can use this for VOIP and Skype telecommunications. Share your self with greater depth with Audio and video.

· Precision glass lens: Experience twice the image clarity with the five-lens system.

· True 1.3-megapixel sensors with RightLight 2 Technology: Enjoy astounding sharpness and clarity under any light conditions.

· Integrated Microphone with RightSound Technology: Enjoy crystal-clear conversations, free from echo and annoying background noise.

· Logitech Video Effects: Personalize your conversations with hundreds of avatars and face accessories that mirror expressions and motion.

· HD quality: Record high-resolution (960 x 720) video

· Premium design: Complements any decor with chrome accents and neutral colors

· Snapshot button: Click to snap a still picture.

· Video preview button: Check your image before joining a video call.

· Activity light: Lets you know when you're "live."

· Flexible base/monitor clip: Easily attach the QuickCam on a flat surface, a monitor, or a flat-panel display for convenient use

Jan 7, 2009

Mouse - Adesso CyberPad A4 8.5x11" Digital Notepad and Graphics Tablet

Form Filling / Hand Writing Recognition / 32MB Internal Memory / SD Card Slot for Additional Storage / Bundled with Adobe Photoshop Elements 5.0

Form Filling / Hand Writing Recognition / 32MB Internal Memory / SD Card Slot for Additional Storage / Bundled with Adobe Photoshop Elements 5.0

The CyberPad A4 is the ultimate Notepad for anyone and everyone that takes notes. Bundled with Adobe Photoshop Elements 5.0 for Windows and 4.0 for Mac OS X, it is the only solution that links handwritten notes and graphics to the PC, providing a Digital reproduction for future reference. You can convert your handwriting into digital text and an Optional SD slot makes it perfect for additional storage. You can easily view, edit, organize and Email your handwritten notes on your computer. The 32MB of internal Memory provides 26 directories from A-Z with 99 pages available and can further be expanded with the Integrated SD slot. By connecting the CyberPad to your PC or Notebook through the USB port, it allows you to capture, organize, and share your handwritten notes, drawings, and sketches. Also, you could use the CyberPad in a Landscape format. It can be use as a drawing tablet where you can write or draw on it and your work will display right on your computer screen. With Adobe Photoshop Elements 5.0, see all of your photos in one convenient place, and find photos using visual keyword tags and a variety of viewing options. Experience improved performance that helps you find what you need faster, even when your library grows to include thousands of photos. Take advantage of options that make it easy for you to edit your photos your way. You can perform one-click fixes, count on step-by-step Editing assistance to learn how to improve your photos, or explore advanced options for finer adjustments.

· Box Contents: 1x Digital Ink Pad, 1x Digital Ink Pen, 4x Application and Driver CD, 1x Portfolio, 1x Notepad, 5x AAA Batteries, 1x USB Cable, and 1x Charger

· Active Area: 8.5" x 11"

· Paper Compatibility: Works with any type of paper including regular letter size & A4 size

· Paper Capacity: Around 135 Sheets of paper

· Built-In Memory: 32 MB (Over 150 Digital Sheets)

· Expandable Memory: SD Slot

· Power Saving Mode: 5 Seconds Auto Standby

· Connection: USB 1.1

· 1024 LPI (Lines Per Inch) Resolution

· 160 Reports Per Second Rate

· Digital Ink Pen: 15 Months Battery life with LED low battery indicator

· Battery Life: 4x AAA batteries with 20 hours writing time and 68 hours standby time

· Dimensions: Length 13" x Width 9.9" x Height 0.5"/ Weight: 1.5 pounds

Jan 6, 2009

Wireless - SmartDisk™ Relief Device Manager™

SmartDisk™ Relief Device Manager™ optimizes the ‘total cost of ownership’ of Pressure Relief Devices. The Relief Device Manager collects pressure & temperature data directly at the pressure relief device, analyzes the information for characteristics that can be detrimental to prolonged service life and provides the user with alarms and warnings when it is appropriate to take planned maintenance action, as well as giving an immediate indication when a Pressure Relief Device was activated.

What is the SmartDisk Relief Device Manager?
In its simplest form, Series 1 and Series 2, Relief Device Manager comprises a processor with integral LCD display located adjacent to the Pressure Relief Device in an appropriate enclosure. The processor display normally indicates the raw input signals from the attached sensors but immediately switches to display an alarm (rupture) or warning condition on its own LCD screen in standard text format. Alarm and Warning status can be externally communicated as well using separate relays integral to the processor. Each Relief Device Manager System is customized. This ensures sensitivity to the unique application conditions that are being monitored. The standard SmartDisk Relief Device Manager processor & sensors are approved for use in Intrinsically Safe applications when appropriate barriers are installed. The SmartDisk Relief Device Manager can be extended to multiple pressure relief devices.

SmartDisk Relief Device Manager – Series 1 Designed for:
Applications where a Pressure Relief Device vents to a stable downstream, normally atmospheric pressure condition. In this configuration, the measurement of pressure at the inlet side of a rupture disk informs Relief Device Manager of the differential pressure across the device.

Information Collected:
(Based upon a combination of two analog inputs and one digital input)

  • Pressure conditions at the Rupture Disk Inlet
  • Temperature conditions at the Rupture Disk Inlet
  • Burst Alert Sensor status (disk burst/unburst)

Information Provided:

  • Disk Operating Ratio Exceeded
  • Disk Cycle Life Exceeded
  • Disk Too Hot
  • Disk Rating Heat Affected
  • Disk Burst

SmartDisk Relief Device Manager – Series 2 Designed for:
Applications where a Relief Device Manager vents to a variable downstream pressure condition. In this configuration, the measurement of pressure on both sides of the Relief Device is required to inform the Relief Device Manager of the differential pressure across the device.

Information collected:
(Based upon a combination of three analog inputs and one digital input).

  • Pressure conditions at the Rupture Disk Inlet
  • Pressure conditions at the Rupture Disk Outlet
  • Temperature conditions at the Rupture Disk Inlet
  • Burst Alert Sensor status (disk burst/unburst)

Information Provided:

  • Disk Operating Ratio Exceeded
  • Disk Cycle Life Exceeded
  • Disk Dynamic Cycle Life Exceeded
  • Disk Too Hot
  • Disk Rating Heat Affected
  • Disk Vacuum Limit Exceeded
  • Disk Back Pressure Exceeded
  • Back Pressure Present
  • Vessel MAWP Exceeded
  • Disk Burst

SmartDisk Relief Device Manager PackageFor Series 1 and Series 2, this comprises:

  • Processor with display
  • Enclosure appropriate to local electrical requirements (mounting configuration to be advised to BS&B)
  • Pressure sensor(s)
  • Temperature sensor

Additional items required are:

  • Burst Alert® Sensor
  • Rupture Disk Safety Head with appropriate connections for pressure and temperature sensors (or equivalent close coupled installation)
  • Power supply 12 or 24 V DC
  • Wiring requirements need to be specified at time of order.


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