Fiber Optics Illustrated Dictionary - Part 51 ppsx

One ofthe two interface ports ofXA-SMDS systems which is used to specify how the carrier switch sends and receives data from an Interexchange Carrier's IXC's SMDS network.. Anassemblage

Fiber Optics Illustrated Dictionary

provide a forum for participation in the planning and

administration of the General Services

Admin-istration's long-distance telecommunications services

provided through the FTS2000 program Since then,

it has become a focal point for the development and

administration of federal technology programs

interapplication communicationslAC

Atranspar-ent means ofintercommunication between computer

software applications (e.g., between a word

proces-sor and drawing program) A similar concept was

dubbed Compound Data Architecture (CDA) by

Digital Equipment Corporation (DEC) The concept

is now frequently implemented in layered

architec-tures on multitasking systems, but in the early 1990s,

surprisingly, it was not prevalent on desktop systems

Once a user has experienced the ease of moving

around data and images among different types

ofap-plications or among apofap-plications from different

ven-dors, it's hard to go back

INTERBUSAnopen systems frame-based, data bus

interface device standard and protocol for

high-per-formance, distributed networks for manufacturing

and process control INTERBUS standards enable

devices from different manufacturers to exchange

information through standardized profiles for robotic

controllers, peripheral drives, data encoders,

indus-trial valves, etc It is a bit-oriented, synchronous

pro-tocol that is used with sensors and actuators

INTERBUS is implemented on ring-based,

token-passing networks and utilizes a single multipair cable

to interconnect all devices, regardless oftype or level

of complexity See actuator, PROFffiUS

Intercarrier InterfaceICI One ofthe two interface

ports ofXA-SMDS systems which is used to specify

how the carrier switch sends and receives data from

an Interexchange Carrier's (IXC's) SMDS network

The other interface is the Subscriber Network

Inter-face (SNI) See Exchange Access SMDS

IntercastAnIntel term for technology that allows a

consumer to interface the TV set with a computer

hooked up to the Internet, to receive "push

technol-ogy" Webcasts or Netcasts, that is, digital broadcasts

ofinformation and entertainment transmitted over the

Web rather than through television broadcast

air-waves or television cable services The digital

infor-mation from the Web is displayed in the blanking

spaces of the TV signals, so the TV can still receive

normal TV broadcasts in addition to displaying

Intercasts See Webcast

Intercept ServiceA service in which a call to a

changed or disconnected number is routed to a

record-ing or, if a recordrecord-ing is not available, to an Intercept

operator In the case of the latter, the caller will be

verbally asked for the destination number and the

operator will attempt to complete the call

InterchangeA commercial Internet connection

ser-vice from Ziff-Davis, similar to some of the other

large Internet Service provisions, but with a slightly

more technological slant

Interchange CarrierIC A common

telecommuni-cations carrier that provides inter- or intra-LATA

ser-vices through local public exchanges according to

definitions and regulatory guidelines established by the Federal Communications Commission (FCC) and the Telecommunications Act See Inter Exchange Carrier

Interchange FormatSee Rich Text Format intercom abbrev. intercommunication, inter-communicator A set of at least two devices, mini-mally a transmitter (with a microphone) and receiver (with a speaker) or two transceivers, over which re-mote communication can take place in at least one direction Most intercoms are audio only, but audio/ visual intercoms are becoming more prevalent as the technology becomes more readily available Intercoms can generally be categorized as wired or wireless Wired intercoms sometimes use existing wiring (e.g., doorbell wires in the walls of houses) Wireless intercoms use broadcast frequencies sent through the air or sometimes through building ing using the AC sockets as an interface to the wir-ing for better transmission

Many wired and wireless intercom speakers are wall mounted, like the PAsystems in schools or hospitals, and the transmitter may be attached to a handheld mi-crophone or operated through a telephone handset Baby monitors are a type of wireless mobile inter-com, in which one unit is placed near the baby and the other is placed near the parents or babysitter or attached to their clothing so they can move around Intercoms are often incorporated into phone systems,

so that the handset or speakerphone is the transmit-ter and the receiver is a speakerphone on another con-sole (or on several concon-soles in broadcast mode) The distinction between wireless intercoms and wire-less radios is not a hard and fast one; there is overlap

in capabilities between sophisticated intercoms and simple radio systems; the main difference is in ease

of use Intercoms and basic two-way short-distance radios tend to be unlicensed push-button devices, whereas wireless radios tend to be licensed devices, some requiring a higher level ofexpertise to operate

In this sense, a computer videoconferencing system can be called an intercom system Once the software application is installed and launched, theu~erneed only sit in front of a microphone and small camera

in order to communicate with the person at the other end of the connection No sophisticated skills are needed and even the push-button aspect of the com-munication has been eliminated

Since videoconferencing systems aren't subject to the same distance restrictions as low-power wireless de-vices, it's possible that small flat-screen monitors with built-in speakers will eventually replace traditional intercoms Parents will be able to readily see what their kids are doing in daycare or at school Friends can keep in touch without making long-distance calls Business associates can discuss important projects or interact in meetings from home or a remote office (or from the road with a wireless modem) When high-speed communications become available to a major-ity ofusers, Internet intercoms may well become one

of the most prevalent telecommunications technolo-gies See public address system, videoconferencing

Anassemblage of committees, subcommittees, and

working groups providing expertise and notification

to the International Telecommunication Union (ITU)

regarding the allocation and management of radio

frequency spectra IRAC develops procedures,

pro-cesses requests, and assists in assigning frequencies

to U.S Government radio stations IRAC includes

the Frequency Assignment Subcommittee (PAS), the

Spectrum Planning Subcommittee (SPS), the

Tech-nical Subcommittee (TSC), the Radio Conference

Subcommittee (RCS), and the International

Notifi-cation Group

Interexchange Carrier Compatibility Forum

ICCF.Anorganization that developed an expansion

plan for telephony Carrier Identification Codes

(CICs) when they became scarce in the late 1980s

The ICCF also served as a liaison in standardization

efforts for fiber interconnectivity in the mid-1980s

interfacen.A hardware connection, or logical

con-nection or translation point between two or more

de-vices or transmissions media Interfaces are an

intrin-sic part ofinterconnected computers, peripherals, and

networks Almost every aspect ofdata and electrical

connections in the telecommunications industry uses

a different format or version of a format, and the

in-terface is the point at which all these different

hard-ware and softhard-ware junctions come together Common

electronic interfaces include docking bays, cradles,

cable connectors, peripheral card connectors, card

slots, and chip sockets

interface, human-machinen.The point of contact

or translation between humans and machines

• A hardware interface is a device or system that

translates human movement, speech, or sensory

output into impulses (usually electromagnetic or

mechanical, though chemical interfaces also

ex-ist) that the machine or computer device can

in-terpret and compute into data and instructions or,

conversely, that translates machine signals into

sensory output or information meaningful to

hu-mans

Human-machine interfaces come in many

vari-eties, including digital, analog, mechanical,

chemical, or a mixture of these Examples of

hardware input interfaces include microphones,

keyboards, joysticks, temperature sensors, serial

connectors, video cams, data gloves, and pressure

pads Hardware output interfaces include

moni-tors, speakers, pulsing lights, thermostat

control-lers, infrared device controlcontrol-lers, and more

• A software interface is a system of algorithmic

procedures/functions to meaningfully

communi-cate information and options to humans and/or to

interpret human communication and sensory into

machine instructions

Common software interface conventions include

the use of textual queries and responses,

graphi-cal pointers, folders, menus, and other culturally

meaningful icons that indicate the state ofthe

de-vice, availability of services, current point in a

process, etc

of trial-and-error combined with the sometimes id-iosyncratic preferences of the people who design the applications or market the devices to the general pub-lic At the present time, software interfaces are often developed intuitively by computer programmers with little or no input from users even though they are in-tended to satisfy the needs of a broad spectrum of people, rather than the more individual needs and preferences of the programmer, in order to produce products with commercial viability

Unfortunately, interfaces become entrenched even if they are no longer appropriate or practical Early ver-sions ofa technology are often designed to overcome pioneering design limitations As the limitations are overcome, the increasingly inefficient interface may

be retained because users have become accustomed

to it or because it is expensive to change production lines The QWERTY typewriter keyboard layout is a good example.Itwas designed for historic manual typewriters and laid out with the letters organized so they wouldslow downthe typist to help prevent jam-ming that occurred with old-style mechanical keys When electric typewriters and computer keyboards were developed without the jamming problems, the QWERTY layout was retained even though the origi-nal reason for the layout became irrelevant The concept of the interface is an important one as it influences how comfortably and efficiently humans can utilize a technology Ease of use and interface design are essential to the success and proliferation ofmany telecommunications products Interface de-sign also reveals priorities; sometimes humans are expected to adapt to the limitations of a technology rather than the technology being designed to serve the needs of humans

Interface Control Application Programming In-terfaceICAPI A telecommunications call control library that facilitates network interface access for T1 robbed-bit signaling systems or TIlE 1 CAS It fits between the operating device drivers and the appli-cation There are similar call libraries for ISDN and ANAPI.AnICAPI protocol uses bit transitions and in-band signaling to establish calls and transmit call information Events and channel states may be logged

Interface Data UnitIOU In ATM networking, in-terface control information transferred to and from the upper layer in one interaction across the layer A service data unit (SOU) may be passed across ATM Adaptation Layer 5 (AAL5) as an IOU correspond-ing to one protocol data unit (DPDU) in a one-to-one correspondence or, depending upon the type of ser-vice (e.g., message or streaming mode), the SDU may also be passed across AAL5 in more than one IDU Interface DeviceInFrame Relay networks, the In-terface Device provides a link between an end device and the network through encapsulation See encap-sulation, Frame Relay Capable Interface Device interference Extraneous, unwanted signals that hinder transmission or perception of the desired sig-nal Types of interference include noise, static, pops,

Fiber Optics Illustrated Dictionary

crackles, echo, babble, chatter, crosstalk, cosmic

noise, and background noise See individual entries

in this dictionary for details.

interference gratingA grating created through a

photoresist laser etching process by exploiting the

in-teraction between the intersection ofcollimated light

beams ofthe same wavelength It is sometimes called

a holographic grating due to the three-dimensional

tapered effect between high and low points in the

grat-ing The sinusoidal cross-section makes it difficult to impose a blazed pattern on an interference grating, putting some limits on the efficiency of this type In-terference gratings came into practical use in the late 1960s They are favored over ruled gratings for a number of precision applications due to greatly re-duced incidence of stray light, particularly in grat-ings with fine grating periods (reduced distance between adjacent facets) Photographically etched

Interferometer Examples

Type Abbreviation Description

Fabry-Perot FPI

Mach-Zehnder MZI

A high-resolution interferometer utilizing multiple reflections from two proximate reflective surfaces A Fabry-Perot interferometer with Michelson-type mechanical motion was designed by the National Bureau of Standards (NBS) in the early 1900s to make the first precision measurements of wavelengths published by the NBS.

In cooperation with the University of Pittsburgh, MIT uses this type of interferometer with a cooled gallium-arsenide photocathode photomultiplier as a detector, with a computer as a controller, for night sky observations There are FPIs installed in the Antarctic, Norway, and many other locations to remotely sense upper atmosphere wind and temperature conditions Doppler concepts are incorporated into the sensor readings for meteorological observations.

Fabry-Perot filters have also been suggested by Wickham et al for use as sub-band tuning mechanisms (in conjunction with Bragg reflection gratings) for optically channelizing radio frequency (RF) signals for spectral analysis ofthe very high frequencies now used for communications signals Bragg reflection gratings and FP filters have further been described by Bao et al as a mechanism for determining wavelengths of transmitted or reflected light through a calibrated wavelength reference, thus creating a reference system.

A basic type of image plane interferometer useful for noncontact testing of surface characteristics and for telescope design The Fizeau interferometer produces a direct image from the source and does not incorporate the same degree

of beam diversion characteristics as the other interferometers mentioned here The FI is used in many astrophysical applications More recent digital phase-shifting FIs have been developed by CSIRO for in-house precision metrology of optical components.

A historic interferometer descended from the Twyman-Green interferometer With improvements, the MZI is still common as a calibration and diagnostic

instrument It is most often used in aerodynamics, thermal transfer, and plasma physics, but is also being studied in fiber optics research.

The MZI is favored for many educational applications, as a basic model can be built by students in a rectangular or parallelogram configuration Depending upon the alignment of the reflecting surfaces, interference fringes mayor may not be produced and, by controlling the length of the optical path, phase shifts can be introduced in a controlled manner The extent of the shift provides a means to monitor relative changes in the optical path, thus providing useful measurement information The beam phasing characteristics of an MZI can also be modeled in computer software.

The MZI is both simple and sophisticated, depending upon how it is implemented It is not only a good student project, but also has been proposed for use as an atomic interferometer.

MZIs are useful in the fabrication and testing of components and various sensors used in telecommunications They have also been incorporated into integrated circuits for converting optical wavelengths and have been developed into directional coupler switches.

cont.

shapes than machined ruled gratings On the other

hand, they also tend to require higher intensity light

sources than ruled gratings

By placing photoresistive material in an

interfero-meter and controlling the angle at which a light beam

hits and rebounds from a reflective surface, it is

pos-sible to have a single light source etch a standing wave

interference pattern, with the angle related to the

dis-tance between grooves If two planar beams of the

same wavelength and intensity (at the point of

inter-section) are aimed from slightly different directions

onto a planar photoresistive surface, they will etch

out a regularly spaced, grooved classicalgrating

Other types ofwaves and other imaging surfaces

ex-ist, some of which are useful for compensating for

the characteristics of other components, but the

abovementioned are common in the fabrication of

semiconductor gratings See diffraction, grating,

interferometer, photoresist, ruled grating

interference guard band See guard band

interferometer Because of its wavelike properties,

a beam ofcoherent light can be split and realigned in

such a way that factors that interfere with one of the

beams can be detected when compared to an

unim-peded reference beam or, more simply, the split beams

can be compared to detect subtle changes to one or

more of the beams Thus, a device that detects and

displays interference between two or more light wave

trains and, optionally, compares wavelengths against

Because light technologies can be very precise, com-pared to mechanical devices, interferometers can be used for very fine detection and calibration The in-terference pattern information derived from an inter-ferometer is useful in measurement or calibration, for example, to determine angular positions in satellite tracking A series of horizontal or vertical measure-ments at precise distances along a path can yield data that can be processed to yield planar information (e.g.,

a height profile in an optical fiber)

There are a variety oftypes of interferometers, rang-ing in complexity from simple lab-built student mod-els to more sophisticated instruments that incorpo-rate integincorpo-rated circuit (IC) concepts There are also different modes for which an interferometer can be designed The optical path length of a test and refer-ence beam can be changed in their relationship in a series ofphase shifts In an optical fiber, the result is

a lateral shift in the interferometric fringe pattern to measure the dimensions of a surface Another ap-proach is to scan down through a fiber to produce an interference signal along a series of points on a sur-face With digital processing, the data can be as-sembled to generate a surface height profile Interferometers have been proposed as instruments

to determine electrical states in silicon-based inte-grated circuits (ICs) and as diagnostic instruments for optical computer networks One interesting applica-tion is the light-in-flight speckle interferometer Interferometer Examples, cont

Type Abbreviation Description

Michelson MI A basic interferometer developed by A.A Michelson to conduct the

Michelson-Morley experiment in the 1880s The scientists used the interferometer to

determine whether a theoretical medium called the aether existed and could be

detected Michelson received a Nobel Prize in 1907 for his discoveriesinoptical science

In a Michelson interferometer, a monochromatic point light beam is split in two

by a partially reflective material, such that one beam continues in the original direction, and the other is reflected (usually 90°) from the original course The beams are recombined with the resulting interference patterns displayed on a screen These are derived from the wavelike characteristics of light and can be analyzed to determine vibrational or thermal effects, which are useful in fabrication and diagnostics The image in a Michelson interferometer is not viewed directly as in a Fizeau interferometer but, in viewing instruments such as telescopes, can be reconstructed

By calibrating the MI with a known reference, the wavelengths of other unknown materials (e.g., gases around astronomical bodies) can be studied through known interference characteristics MIs are also used to develop standards in atomic lengths

Twyman-Green TGI A basic type of interferometer used as an optical fabrication and diagnostic tool,

developed by Frank Twyman and Arthur Green in the early 1900s The modem TGI is based upon a monochromatic point light source at the focal point of a lens

By revealing patterns of optical interference resulting from unequal light paths, the TGI can be used to assess optical surface characteristics such as the flatness of

a surface, performance of a component (e.g., a prism), or deviation from a reference shape

Fiber Optics Illustrated Dictionary

presented by Swedish engineers for evaluating 3D

shapes by using ultrashort laser light pulses On a

software level, algorithms for phase-stepping

in-terferometry have been developed by Chinese

sci-entists

Interferometers are important in many aspects

ofas-tronomy Not only are telescopes based upon

inter-ferometric principles, but Fizeau interferometers (FIs)

are included as payloads on space missions, selected

for their accuracy and capability of sensing over a

wide field The Global Astrometric Interferometer for

Astrophysics (GAIA) mission, for example, includes

three stacked, mechanically connected FIs designed

to observe about 50 million stars

Historic interferometers were based upon

noncoher-ent, mixed-wavelength light, while interferometers

developed since the invention of lasers typically use

coherent, nearly monochromatic light The

Interfer-ometer Examples chart includes a short list of some

common, representative interferometers used in

re-mote sensing, and component fabrication and testing

applications relevant to telecommunications

Interferometers may be further optimized for a

par-ticular task such as assessing thecleave (terminal cut)

ofan optical fiber by forming an interference pattern

between the fiber surface and an optical reference A

CCTV camera or other display device may be used

to enlarge and display the cleave so the angle and

evenness ofthe cut can be seen Adivergence ofangle

can be counted as a specific number of fringes in a

fiber of a specified diameter The shape of the fringe

pattern can indicate the evenness of the surface The

inteferometer may be customized to be

self-calibrat-ing for this task and accurate within a tolerance of

one fringe, enabling a cut to be accepted or rejected

(and possibly recut), before connecting to other

com-ponents Some interferometers can interpret the

vi-sual information into digital data for further

process-ing, thus enabling lists or graphs ofcomponent

char-acteristics such as angle of cut, smoothness, radius

of curvature, etc., to be generated See beam splitter,

cleave, coherent light, ferrule, spectrometer

interferogramA visual measurement diagram

de-rived from.output from an interferometer Aseries of

interferograms may be digitally processed to

gener-ate a surface height profile of the medium observed

(e.g., optical fiber) See interferometer

Interim Local Management InterfaceILMI A

means of providing an ATM device with status and

configuration information about virtual connections,

and the registered ATM prefixes, addresses, services,

and capabilities available at its ATM Interfaces

through the Simple Network Management Protocol

(SNMP) and an ATM Interface Management

Infor-mation Base(Mill).ILMI is an open protocol that

was developed as an interim solution by the ATM

Forum in the mid-1990s to enable the exchange of

UNI management information through direct

encap-sulation over ATM adaptation layer 5 (AAL5)

How-ever, the interim designation was dropped ILMI is

not universally implemented and meta-signaling may

be used to serve this purpose on some systems

Interim Number PortabilityINP The use ofvari-ous telephone subscriber services, such as call for-warding, call routing, and call addressing, to allow a call to be redirected to another location, usually on a temporary basis

interiorIn ATM networking, an item such as a link, address, or node inside a PNNI routing domain Interior Gateway ProtocolIGP Afamily ofnetwork routing protocols for exchanging information with other routers and switches on the same system When changes occur in the organization of the network, these changes are communicated to the routers, so the routing table databases may be revised accordingly Interior Gateway Routing ProtocolIGRP A Cisco Systems proprietary multipath routing protocol de-veloped in the mid-1980s for routing within autono-mous systems Since then, the protocol has been fur-ther developed and many users have replaced Rout-ing Information Protocol (RIP) with IGRP to run on large, heterogenous networks, like the Internet IGRP was intended to run in a variety of network environ-ments and enhanced IGRP has been developed to sup-port TCP/IP, IPX, and AppleTalk

IGRP-enabled routers send some or all of their rout-ing tables to neighborrout-ing routers at regular intervals,

a process that also enables distances among nodes to

be calculated as the information propagates out through the network

interlaceAsystem used in frame-based video image display to display images in two-frame passes, with one pass imaging the odd lines and the next the even lines (or vice-versa), in an alternating pattern Thus,

in NTSC, for example, an interlaced screen is imaged

in two fields of262.5 lines (to make up the full 525 scan lines), each field taking 1/60 ofa second Some flicker can be seen on an interlaced display, so non-interlaced monitors, including multisync monitors, have become prevalent on computer systems Gen-erally, the faster the refresh, the more stable the im-age See cathode-ray tube, field, frame, interleave, multisync, scan, scanning rate

interleavev.t. 1 To arrange in alternating layers, rows/columns, or time slices 2 In concurrent pro-gramming, a logical means to execute sequences in order to analyze the correctness of concurrent pro-grams 3.In networking, to transmit pulses through

a single path through time-division from more than one source 4 In graphics file storage and display, a means ofarranging the image data so that all odd lines ofthe image and all even lines ofthe image are stored

or displayed as a group 5 In magnetic and magneto-optical data storage, a means and pattern of storing information on a disk so that the physical character-istics of the read/write sequence are accommodated without the drive head needing to "backtrack" to find the next section ofdata 6.In multimedia applications,

a means ofslicing up the recording space so that dif-ferent media (sound, graphics, etc.) are laid down in strips or sections on the tape or disc 7 A data trans-mission error-correcting technique in which code symbols are arranged in an interleaved pattern before transmission and reassembled upon receipt

is constructed and displayed by alternately scanning

all even lines and then all odd lines This system of

display is commonly seen on televisions screens and

on some NTSC-compatible computer screens A

cer-tain amount of flicker is usually noticeable on

inter-leaved displays See interlace

interleaverInfiber optics systems, a multiplexing

component that can increase channel density Filters

may be used to receive channels or route channel

groups See add/drop multiplexer

intermediate frequencyIF In heterodyne receivers,

the beat frequency created as a result of the

differ-ence between a locally generated signal and the

in-coming radio signal See beat frequency

Intermediate Signaling Network IdentificationIn

Signaling System 7 (SS7), a capability that allows an

application process in the originating network to

specify intermediate signaling networks for

noncircuit-associated signaling messages, and/or to

notify an application process in the destination

net-work about intermediate signaling netnet-works

intermittent errorsFault conditions that happen

occasionally, sometimes without apparent pattern, or

occur from specific causes that happen seldom or

ir-regularly Difficult to anticipate and diagnose,

inter-mittent problems are often not alleviated until a

pro-gram has been run hundreds of times or a computer

or phone network has negotiated thousands of calls

intermodulation distortionA type of audio

distor-tion that occurs when multiple tones interfere with

one another in a way that is not harmonically related

to the original tones

internal modemAcomputer modem installed inside

a larger system that is utilizing the modem Internal

modems are usually powered by the system in which

they are housed and usually take the form of small

PC boards or very small PCMCIA cards Sometimes

referred to tongue-cheek as "infernal modems,"

in-ternal modems can be finicky to install in systems

with several peripherals that require IRQs

Internal modems are convenient in that they are out

of sight and mind, and don't take up extra space - a

real plus on laptop computers They have

disadvan-tages as well, as they are often machine- or

platform-specific and often can't be reinstalled in a new

com-puter of a different type, as can most external

mo-dems External modems are easier to swap among

systems, can be shared by a number ofusers through

a switcher, and usually have status lights that are

handy diagnostic tools Since most internal modems

install in a slot that faces the back ofthe system, they

often don't provide status lights.Ingeneral, people

prefer internal modems on small mobile devices and

external modems on desktop systems or systems with

shared resources

International Ad Hoc CommitteeIAHC See

Inter-net International Ad Hoc Committee

International Alphabet No.2An older alphabetic

coding system of equal-duration pulses of negative

and positive volts (called marks and spaces) in groups

offive, to represent character signals The beginning

nal and a stop signal The use of five elements in two possible polarities results in 25or 32 character en-codings Even for a basic alphabet, this was some-what limited, and schemes to double the number by allowing a code to represent one of two characters were devised

Something similar happened later with computer character codes International Alphabets evolved into ASCII and became widely implemented on comput-ers, but there were only 128 charactcomput-ers, insufficient for accents or math symbols Many developers added

128 codes for a total of 256 characters and called it

"extended ASCII." Technically, the extra codes weren't standard ASCII and were not consistent across platforms Another limitation was that they couldn't be used together, the user had to select ASCII

or "extended ASCII" banks In the mid-1980s, the Amiga and Mac removed this limitation, enabling individual addressing of letters in both See Appen-dix for an ASCII chart See ASCII, Unicode

International Amateur Radio UnionlARD Aregu-latory agency and proponent of world amateur radio activity established in France in 1925 Amateur ra-dio organizations throughout the world interact with

a high degree of cooperation and communications

The IARU is essentially to global amateur radio com-munications what the American Relay Radio League (ARRL) is to American amateur radio The IARU is organized into three regional organizations that par-allel administrative divisions of the International Telecommunication Union (ITU) See American Ra-dio Relay League http://www.iaru.org/

International Atomic Time, Temps Atomique In-ternationalTIA.Anatomic time scale based on the coordinated efforts of more than 200 atomic clocks from more than 50 centers from around the world, which are maintained in France by the Bureau Inter-national des Pods et Mesures Unlike the Coordinated Universal Time (UTC), which is adjusted occasion-ally in leap seconds to maintain some coordination with the Earth's axis rotation, TIA is not adjusted, but remains consistent with atomic time scales Other-wise, TIA and UTC are very similar See atomic clock, Coordinated Universal Time

International Business MachinesffiM.Inthe late 1800s, Herman Hollerith, an American engineer, evolved the concept of punched cards as a storage medium and applied it to the development of a tabu-lating machine, an early computer that could be used

to store and process information in categories This resulted in Hollerith cards, Hollerith code, and a ma-chine which could tabulate the vast amount of cen-sus data gathered at regular intervals in the United States The tabulating machine dramatically im-proved the efficiency of storing and analyzing cen-sus data, and Hollerith formed a company called the Tabulating Machine Company This later merged with several other companies to form the Computer-Tabu-lating-Recording Company, which sold a wide range

of industrial products

Thomas 1 Watson, Sr left NCR to join the company

' • : )i:J(:: : • ::• :: •..•:.': :: :

~j

Fiber Optics Illustrated Dictionary

as general manager in 1914, and remained with the

company for over four decades, eventually passing

on the position to his son, Thomas J Watson,Jr

On Valentine's Day, in 1924, the name ofthe company

changed to International Business Machines

Corpo-ration IBM became an enormously influential

com-pany in the business and computing market, and

funded or partially funded the research and

develop-ment of several historic room-sized computing

ma-chines IBM's research laboratory has contributed a

great legacy of original and fundamental scientific

discoveries of interest both inside and outside the

computing industry IBM inventions are awarded

more than 1000 patents per year; in other words, IBM

develops as many unique inventions in a single year

as the best individual inventors of the 1800s

devel-oped in their entire lifetimes

In 1975, IBM released its first microcomputer, the

IBM 5100; it was not a commercial success, and it

was not until 5 years later that the first of the long

IBM PC line was introduced to the public This time

sales were good, particularly in the business market,

and IBM and IBM-licensed personal computer

tech-nology became the most common platform for

desk-top computing See Hollerith, Herman; IBM Personal

Computer, Jacquard loom

International Center for Technology Assessment

ICTA Anonprofit, bipartisan organization dedicated

to helping government officials and the public in

un-derstanding technology and how it affects human

society and the environment ICTAexplores and

com-municates the social, economic, ethical, political, and

environmental impacts related to the manufacture,

distribution, and application of technologies ICTA

also uses legal petitions, comments, and litigation to

fight against harmful deployment of technology

http://www.icta.org/

International Commission on Technology and

Ac-cessibility ICTA A commission to explore

develop-ments in technology that may assist people with

dis-abilities and to promote and disseminate their

under-standing and use ICTA was founded in the 1960s in

Sweden in conjunction with Rehabilitation

Interna-tional (RI) and the Swedish Handicapped Institute

In 1969 ICTA and RI developed and adopted the

In-ternational Symbol ofAccess (ISA)

http://www.ictaglobal.org/

International Commission for Optics ICO.An

in-ternational organization affiliated with the

Interna-tional Union of Pure and Applied Physics the

sup-ports and promotes the dissemination of knowledge

in optics, founded in 1947 http://ico-optics.org/

International Correspondence Chess Federation

ICCF This is one ofthe more interesting historic

bod-ies using telecommunications to enhance gaming

communications The ICCF has evolved from the

lnternationa/er Fernschachbund,founded in 1928,

which was succeeded by the International

Correspon-dence Chess Association, in 1945, to become the

ICCF in 1951 Correspondence chess hasn't only

been conducted through postal mail services ICCF

members and chess players in general have always

been technology conscious and have enjoyed their matches through the use of homing pigeons, tele-grams, trains, planes, computer modems, and high-speed connections to the Internet

International Data Encryption Algorithm IDEA

A European-designed, 128-bit, single-key encryption algorithm used for data security It has been incorpo-rated into Pretty Good Privacy (pGP) partly because

it doesn't have the same U.S export restrictions as other encryption algorithms Use of IDEA is license-free for noncommercial use See encryption, Pretty Good Privacy

International Development Markup Language IDML AnInternet protocol and associated set of standards to facilitate development in a global con-text In 1998, the Development Markup Language (DML) was seen as a means to support the markup

of information on computer networks that describe developmental activities and mandatory data ele-ments described by relevant standards It was in-tended to be consistent with other metadata schemes and capable of multilingual markup In February

1999, DML was renamed IDML The IDML Work-ing Group was formed to develop recommendations and a process for electing an IDMLAdvisory Group

It is recommended that XML be used for Site Descrip-tion files even though other formats may be used Extended IDML is a superset of the Core Activity Schema with additional audit trail and informational items IDML was established as a pilot standards-track candidate in early 200 I See Extensible Markup Language, IDML Initiative

International Electrotecbnical Commission IEC

Aninternational standards-development and recom-mending body, founded in 1906 as a result of a 1904 resolution at the Electrical Congress The IEC pub-lishes standards for electrical, electronic, magnetic, and related technologies and promotes cooperation among member countries IEC standards form the core of the World Trade Organization's Agreement

on Technical Barriers to Trade (TBT) Hundreds of technical committees and working groups carry out the mission of the IEC Technical committee papers are submitted to a full-member National Committee members' vote in preparation for approval as inter-national standards http://www.iec.ch/

International Engineering Consortium lEe A nonprofit professional organization supporting engi-neering research and education sponsored by univer-sities and engineering societies, founded in 1944 The focus of the organization has broadened from a na-tional to internana-tional purview and from electronics

to information engineering IEC sponsors courses, conferences, virtual exhibits, and a number of publi-cations http://www iec.org/

International Federation for Information Process-ing IFIP Anonprofit, nongovernmental, information processing research organization IFIP was estab-lished in 1960 under the auspices of UNESCO after the first World Computer Congress of 1959 A num-ber oftechnical committees provide expertise on tech-nological matters http://www.ifip.or.at/

international series of workshops, founded in June

1998, intended to bring together professionals and

experts in law to respond to White Paper

recommen-dations for assigned numbers on the Internet

The process of open discussion and the goal of

self-regulation were key aspects ofthese proceedings The

Internet community believed that it was possible for

those in the industry to produce a viable system for

assigning Internet addresses without government

takeover ofthe process and used the Internet itselfas

an important venue for meetings, opinions, and

some-times heated debates over how addresses would be

allocated and assigned

As a result of initial discussions, a California

non-profit public benefit corporation called the Internet

Corporation for Assigned Names and Numbers

(ICANN) was tendered as a draft recommendation

as a means to coordinate the administration of

Inter-net domain names and InterInter-net Protocol (IP)

ad-dresses The draft proposal, jointly presented by

Net-work Solutions, Inc and the Internet Assigned

Num-bers Authority (lANA), was discussed in September

1998 by IFWP with regard to how it fell within a

model of common principles and structure specified

by the u.s. Department of Commerce Statement of

Policy on the Management of Internet Names and

Addresses. Three proposals were presented to the

Deptartment of Commerce in October 1998 by

dif-ferent groups, and testimony was presented on

trans-ferring the Domain Name System to the private

sec-tor ICANN's bylaws and its first public meeting were

held in November 1998 See Intemet Assigned

Num-bers Authority, Internet Corporation for Assigned

Names and Numbers, InterNIC

International Frequency Regulation BoardIFRB

Anagency established by the International Telegraph

Union in 1868 to manage the broadcast frequency

spectrum In 1912, the IFRB's Table ofFrequency

Al-locationsbecame mandatory The frequency

alloca-tion table specified frequency bands for specific uses

in order to minimize interference among stations See

Federal Communications Commission, International

Telegraph Union

International Information Systems Security

Cer-tification ConsortiumISC2 Anonprofit corporation

established in 1989 to develop certification programs

for security professionals working in the informations

services field http://www.isc2.org/

International Intellectual Capital Codes

Associa-tionIICCA A not-for-profit association tasked with

defining a comprehensive lexicon of skills of

inter-est to industries and users for employment/employee

matching through the iCAP Catalog and the

Intellec-tual Capital Inventory (iCAP) system IICCA is

re-sponsible for the development, maintenance, and

uniformity of the iCAP Catalog See iCAP

International Internet AssociationAfee-based

In-ternet service that provides access to more than

20,000 databases from around the world

International Internet Industrial AssociationlIlA

Aprofessional association ofInternet Service

Provid-others directly influencing or being influenced by the development of the Internet The IlIA is concerned with issues such as the addition of a larger available base of international Top Level Domains (TLDs) http://www.iiia.org/ http://www.iatld.org/ International Mobile Subscriber Identity IMSI.An lTU-T identification number assigned by a wireless carrier to a mobile station to uniquely identify the sta-tion locally and internasta-tionally

International Network for Development Informa-tion ExchangeINDIX Acoalition for organizations involved in development in information exchange INDIX developed the CEFDA standards for data ex-change and participated in the development of the International Development Markup Language (IDML) See IDMLlnitiative http://www.indix.org/ International Organization for Standardization (International Standards Organization)ISO.An important international standards-setting body which has produced many of the specifications and docu-ments used by telecommunications professionals ISO is familiar to many through its ISO-9000 series

of quality assurance specifications ISO-9000 stan-dards can be summarized as "Say what you do, then

do what you say, and get it certified, if necessary." http://www.iso.ch/

International Radio Consultative Committee CCIR A standards and regulatory-recommending body founded in 1927, descending from the Interna-tional Radiotelegraph Conference in 1906,in connec-tion with the Internaconnec-tional Telegraph Union This or-ganization was formed in response to public broad-casts over radio waves in the early 1920s See Inter-national Telecommunication Union (ITU-R) International Radiotelegraphic ConventionOne of the early international gatherings, resulting from the growth oftelegraphy, resulted in a multinational con-sent agreement regarding Protocol and Service Regu-lations that was documented in November 1906 The convention was to be entered into force in July 1908

by Great Britain, Germany, Austria, Hungary, Den-mark, and a number of other European nations, Ja-pan, Argentine Republic, Brazil, Chili, Uruguay, Rus-sia, Turkey, Persia (now Iran), the U.S., and Mexico The convention defined various types of telegraphic establishments common at the time, including coast and ship stations, and delineated operating parameters

to ensure cooperation in the use oftelegraphic trans-missions and designated frequencies, responses to distress signals, telegraphic charges, and other tele-graphic matters ofinternational importance See Ra-dio Communication Laws of the United States International Society for Measurement and Con-trolISMC Formerly the Instrumentation Society of America (ISA), ISMC is a nonprofit professional or-ganization supporting manufacturers and engineers involved in the theory, design, manufacture, and use

of measurement and control instruments and com-puter systems See Instrumentation, Systems, and Automation Society

http:/www.isa.org http://www.isaca.com/

Fiber Optics Illustrated Dictionary

International Special Committee on Radio

Inter-ference CISPR An international committee with

members from a broad spectrum of the radio

com-munications/engineering industry who work to

pro-mote international agreement on aspects ofradio

in-terference to facilitate international trade CISPR is

composed ofa number ofinternational organizations

plus each National Committee of the International

Electrotechnical Commission (IEC)

Through conferences and subcommittees, CISPR

promotes and produces information guidelines,

sta-tistical methods, and standards related to the

protec-tion of radio recepprotec-tion from interference from

con-sumer goods and industrial equipment, electrical

sup-ply systems, and broadcasting equipment CISPR

es-tablishes limits and requirements for immunity to

in-terference and takes into consideration safety

regu-lations as they affect interference suppression

ofelec-trical equipment Ofparticular interest to

telecommu-nications are CISPR publications on electromagnetic

compatibility (EMC) and emission standards

http://www.iec.ch/

International Speech Communication Association

ISCA A nonprofit organization promoting

interna-tional speech communication, science, and

technol-ogy originally founded in 1988 as the European

Speech Communication Association, ISCA was

es-tablished in 1999 It is now an independent,

self-sup-porting organization ISCA's interests include

re-search in synthetic speech development and

process-ing http://www.isca-speech.org/

International Switching CenterISC A gateway

exchange whose function is to switch

telecommuni-cations traffic between national and international

countries

International Telecommunication Regulations

ITR A set of international regulations intended to

supplement the International Telecommunication

Convention while also recognizing the individual

rights ofnations to regulate their telecommunications

sectors The ITR framework seeks to promote the

efficiency, harmony, and evolution ofglobal

telecom-munications through established general principles

for international telecommunication transport media

and services offered to the public Draft proposals of

the ITR were presented at the world Administrative

Telegraph and Telephone Conference in Melbourne,

Australia, in 1988 per a resolution of the

Plenipoten-tiary Conference of the International

Telecommuni-cation Union (ITU)

International Telecommunication Union ITU.A

significant, influential, global United Nations

stan-dards agency descended from the International

Tele-graph Union The lTU, headquartered in Geneva,

Switzerland, provides extensive publications,

pro-motes communication, sponsors international

meet-ings and conferences, disseminates news, and

devel-ops standards and regulations The lTU oversees a

number of subgroups, called sectors (see chart)

The lTU is involved in a number of important

com-munications venues for discussion and the

dissemi-nation of findings Examples include:

• The publication of the lTUOperational Bul-letin every 2 weeks to report on the

adminis-trative and operational information exchanged among administrators, service providers, and recognized operating agencies (ROAs); coun-try codes and other statistical indicators are published in conjunction with the bulletin as annexes

• The organization of the World Radio-communication Conference (WRC) to admin-ister international agreements in wireless tele-communications technologies

• The organization ofthe World Telecommuni-cations Standardization Assembly to deter-mine needs and priorities related to standards development and dissemination

The convening of a Plenipotentiary Confer-ence every 4 years (1998, 2002, etc.), an im-portant meeting ground for member states where decisions on direction and policy are made and previous actions reviewed and de-bated The 1998 conference was characterized

by calls for greater involvement ofthe private sector in lTU activities When the council is not convened, administration and oversight of the lTU is handled by the lTU Council See Telecommunication Standardization Bureau For

a briefdescription oflTU-T history, see International Telegraph Union For series lists and individual rec-ommendations, see Appendix C and alphabetized lists under letter designations http://www.itu.int/ International Telegraph Union lTU An old and influential organizing and standards-recommending body formed in 1865 when the telecommunications industry was beginning to boom The lTU was cre-ated in response to the need for cooperation and for-mal agreements related to the installation and use of multinational telegraph systems Twenty participat-ing countries signed the first International Telegraph Convention

After the invention of the telephone, the Telegraph Union drew up recommendations for legislation gov-erning international telephony Radio communica-tions began to develop, so the Telegraph Union con-vened a preliminary radio conference in 1903 lead-ing to the Radio Regulations and foundlead-ing of the In-ternational Radio Consultative Committee (CCIR)

In 1934, the name was broadened to International Telecommunication Union It became an agency of the United Nations in October 1947, and the head-quarters was transferred from Berne to Geneva in 1948

The Union later became known as the CCITT, as there were a number of cels set up for different areas of communication in the 1920s; the CCIT and the CCIF were amalgamated in 1956

In 1992, an important conference took place in which the organization was evaluated with the aitp of up-dating it to align with the complex, changing envi-ronment of current and future technologies The or-ganization has recently been renamed International Telecommunication Union (ITU) because the

funda-International Traffic in Arms RegulationsITAR.

Rules issued by the U.S State Department, under the

authority of the Arms Export Control Act, to control

the export/import ofdefense-related articles and

ser-vices, including information security systems such as

cryptographic systems and TEMPEST suppression

technology

International World Wide Web Conference

CommitteeSeeWorldWideWeb Conference Committee

ITV-D Telecom Development Sector

Facilitates global telecommunication

development by providing organizing and

coordinating expertise and assistance The

lTV-D works through conferences, study

groups, the Telecommunication

Development Advisory Group, and the

Telecommunication Development Bureau

(BDT)

essentially the same today as they were over 100 years

ago, and the convergence of the many media and

communications technologies through digital

trans-mission has united many formerly separate areas

(Source:elTU-TWeb site history.)

In Canada, communication with the lTD is

accom-plished through the Canadian National Organization

for the lTV (CNO/ITD-T) and the Steering

Commit-tee on Telecommunications ofthe CSA (CSA/SCOT)

See International Telecommunication Union; Morse,

SamueIB.F

ITV-R Radiocommunication Sector

Descended from the International Radio

.Consultative Committee (CCIR), this is the

arm of the lTV responsible for researching

technical and related regulatory issues.It

regulates ground- and space-based radio

frequency telecommunications

ITV-T Telecom Standardization Sector

FoundedinMarch 1993, ITV-T replaces

the International Telegraph and Telephone

Consultative Committee (CeITT) The

ITV-T endeavors to ensure efficient and

on-time production of high quality

standards covering all fields of

telecommunications with the exception of

radio, which is handled by ITV-R The

work of the ITV-T is handled by numerous

study groups and is documented in tens of

thousands of papers Presently more than

2500standards recommendations are in

force that form a framework for global

communications

cally refers to an interconnection oftwo or more data networks While individual networks may be con-nected in any number ofways, it is common to inter-connect them through the Open Systems Interinter-connect (OSI) model as it ensures a good level ofcompatibil-ity with existing technologies and supports interoper-ability among a variety of types of systems See In-ternet

InternetA global communications community of more than 60,000 cooperating networks, evolving in the early 1980s out ofARPANET, now known as the

Internet or colloquially as the Net.

The Internet consists ofa distributed network oftens

of millions of computers linked together through small and large communications services providers

By early 1995, the Internet had more than 4 million hosts and the term was officially defined by the Fed-eral Networking Council

The Net is defined in the Telecommunications Act of

1996 and published by the Federal Communications

" the international computer network of both Federal and non-Federal interoperable packet switched data networks."

The evolution of the Net has been influenced by a broad base of technical and lay interests and an equally wide range of commercial and public inter-ests The vocal promoters of the Net as a universal access communications medium to serve the public good have been joined by commercial interests seek-ing a way to use the Net to further private and public business interests.In the early days, the Net had a high proportion of users in technical and scientific fields and focused on cooperative communication and re-search Since the mid-l 990s, an overwhelming influx

of commercial vendors has changed the character of the Net, but there has also been a large growth in co-operative nonprofit and community organizations

In1993, the United Nations and the U.S White House came online, thus changing the ways to access and think about politics Global doors have opened up to people doing genealogical studies and people are re-discovering friends they haven't seen since elemen-tary school The phone network is undergoing sub-stantial changes due to competition from long-dis-tance email and chat resources that are available on the Internet without long-distance phone costs The impact of the Internet on communications ven-ues and global culture is highly significant and will likely exceed the changes brought about by the in-dustrial revolution The information glut and impact

on personal privacy will be far-reaching as well Speculations about the emergence ofthe Net as a fonn ofdigital intelligence may not be farfetched, and, with the cooperative communication possible among sci-entists and interested lay persons, research will move forward at an unprecedented rate See ARPANET, Telecommunications Act of 1996, RFC 1958 Internet2 Aconsortium of more than 100 academic and nonacademic organizations working to develop

a vision and implementation plan for the next

Sector Notes

ITU-T Subgroups (Sectors)

Abbrev.