Fiber Optics Illustrated Dictionary - Part 21 doc

common carrier A public communications service carrier, usually regulated and licensed by agovernment agency.. Federal Communications Commission FCC that recommends and implements regula

Fiber Optics Illustrated Dictionary

code rejects In packet networking, codes that are not

used or not recognized are processed as code rejects

codec encode/decode, coder/decoder A system to

convert analog signals, such as video and voice, to

digital signals for transmission, then back to analog

at the destination Codec mechanisms were originally

installed on trunk lines, but as the cost of

electron-ics dropped, they moved closer and closer to the home

and office until now, with systems such as DSL, the

codec is installed and performed right on the

pre-mises Contrast with modem

coded mark inversion CM! In SONET and SDH

networks, a two-level non-return-to-zero coding

scheme Binary values are coded in relation to a

bi-nary unit time interval(T).A one (I) is coded for a

full time interval at one of two amplitude levels (low

and high) such that the level alternates for successive

ones Azero (0) is coded by a positive transition from

one to the other consecutive amplitude level at the

midpoint of the time interval for half a binary unit

time interval(T/2).

Code RedAnintrusive program called a worm that

used a unicode encoding technique to infect systems

Abuffer overflow vulnerability in the indexing server

was exploited to insert the worm onto a new system

Once a system had been infected, the worm used it

to perform denial of service attacks on

www.whitehouse.govand,in some cases, defaced the

server's home page It spread by randomly

generat-ing IP addresses for new systems to infect Windows

NT and Windows 2000 systems using the Microsoft

Internet Information Server (llS) were vulnerable In

response, vendors such as Cisco Systems took steps

to update systems to prevent this type of security

breach and Microsoft issued a Security Bulletin

MS01-033 with information on patches

coding violation Cy' In ATM networking, a coding

violation results when bit interleaved parity errors are

detected on an incoming signal Each BIP error

(typi-cally up to 8, 16, or 24) increments a CV counter In

SONET, the section, line, and path errors are located

in their associated overhead frames Thus, in a BIP-8

system, up to 8 xNcoding violations may be

associ-ated with a frame One or more coding violations in

a second on a layer results in an errored second (ES)

or a severely errored second (SES) See bit

inter-leaved parity See RFC 1595

cohere To come together firmly, to be cohesive, to

coalesce, to hold together,join, unite, merge The term

particularly applies to the action of small, discrete

parts or granules

coherent light Light in which the wave lengths are

aligned orillphaseto create a very straight, narrow

beam, in contrast to light from lamps and flashlights

that spreads out and quickly diminishes in intensity

Coherent Light can be generated by lasers and by some

light-emitting diodes (LEDs) Both lasers and LEDs

are used as light sources for fiber optic cables

coherer A device that causes particles to join, lump,

or clump together when exposed to a nearby

dis-charge of electricity or to a current running to the

particles through a wire As the particles are

stimu-lated to arrange themselves in a more coherent fash-ion, that is, to align themselves so that resistance is lowered, they collectively provide a better conduct-ing surface Many early coherers consisted of a glass tube corked at each end with filings sealed inside The coherer was connected in series with a battery-driven electrical circuit

Early experif11ents by O Lodge in 1894, D Hughes

in 1878, and E Branly in 1890 resulted in a cohering apparatus that could behave as an on/off switch by serving as a nonconductor, unless stimulated by a spark, and returning quickly to nonconducting sta-tus once the spark and the current had passed through This useful device was adapted by Marconi for im-provements in radio devices See Branly detector

Marconi&Castelli Coherers

This historic Marconi cohereI' is only a couple of inches long, a delicate glass tubing supported by an ivOly base It is parr ofthe American Radio Museum collection Coherers were the forerunners to rectify-ing crystal detectors in crystal radio sets.

This diagram ofa Castelli cohen!r shows a tube (1) within which are conductor plugs(2,2')separated by

an iron plug (4) and two mercury pockets (3,3 ') This cohereI' was used by Guglielmo Marconi in transat-lantic experimell1s [ScienlijicAmerican, Oct.4,1902.}

coil In its simplest sense, a loop or number of con-tinuous turns of wire or other material The coil may have successive windings that are touching, or that may be spaced and stretched out like a spring Coils are often used in wireless communications technolo-gies where a long length of wire must fit in a small amount of space, where a broader conductive surface area is needed, or where the proximi ty of the wire loops changes its overall conductive properties

Inantennas, receptivity to electromagnetic waves is based in part on matching the length of a lorlg wave; consequently, very long wires are needed for some applications

There are many ways to wind and use coils Tables

length and diameter ofcores, and the gauge and

num-ber ofwindings needed for the wire Open coils with

few turns are used as load coils in voice grade

tele-phone wire installations Wound coils, wrapped

around~metal core, can be used to create an

arma-ture. Sending/receiving coils can be created with

many windings over a core or a frame, utilizing the

thickness ofthe wire, the shape of the coil, and other

characteristics to control which frequencies are

trans-mitted or received Sometimes dual windings are

used, that is, a smaller coil inside a larger one, with

an insulating layer in between A spark coil for a

ba-sic wireless transmitter can be constructed with an

inner primary winding coil and an outer secondary

winding coil encasing a soft iron core Commercial

induction coils, based upon the same structure as the

simple spark coil, were used for decades to generate

intennittent high voltage

One unsettling historical fact is that X-ray coils were

used in the early part ofthe century for sending

wire-less communication signals

Load coils are commonly used on copper telephone

wire installations to improve signals at voice grade

levels, but they cause problems when data is sent at

high speed through the wires, as in digital subscriber

line (DSL) services; DSL transmissions are highly

sensitive to noise and distance See antenna,

arma-ture, basket winding, induction coil, load coil,

wind-ing, winding machine

Armature Coil Windings

Two simple types ofarmature coils are shown here.

On the left is a single coil, on the right, a double coil,

wound in parallel Armature coils can be quite large

and intricate and are the basis ofelectric 'dynamos, '

now more often called generators.

cold dockingHooking components into a base or

desktop unit while one or, preferably, both units are

powered off This is done to prevent danger of

elec-trical shock or damage to sensitive electronic

com-ponents See docking

cold startStarting a system from a power off

condi-tion.In a computerized system, it also means there is

no software online From a cold start, many systems

will run through physical and logical self-test

se-quences and bootstrap sese-quences to load device

drivers or other software which may be needed to

rec-ognize and bring online the rest of the system, and

Collaboration for Interactive Visual Distance LearningCIVDL Videoconferencing technologies applied to distance education for engineering pro-grams The CIVDL is amember ofthe PUG Alliance Colladon, Jean-Daniel(1802-1893) A Swiss-born physicist and engineer, Colladon and his friend, Charles-Fran~ois Sturm, traveled to Paris in 1825 to study mathematics and physics and to continue col-laborating on scientific experiments Both young men became assistants toJ Fourier On their second at-tempt, they jointly won the prize offered by the Paris Academy for research on the compressibility of wa-ter They accurately measured the speed of sound in water and provided important basic research as well

as a chapter in the history of sonar Colladon was in-strumental in the conversion of city lighting to gas,

in the 1840s and demonstrated water as a light guide

He developed a type ofphotometer, to aid him in mea-suring luminosity for his projects Archival collec-tions of correspondence and scientific papers are housed in the Geneva public and universitY libraries and the Swiss library in Bern See Tyndall, John collapsed backboneA backbone is a main artery or trunk in a network system A collapsed backbone is one in which the physical connections are

incorpo-rated into a centralized intelligent hub or network center,providing easier access and administration collateTo assemble in the desired order Many print-ing programs, word processors, desktop publishprint-ing programs, and photocopy machines now have set-tings that allow you to choose, for multiple printouts

of a multipage document, whether it is to be printed sequentially or in page groups Collation is the elec-tronic substitute for lining up three card tables in a row with a pile of each page of a twenty-page docu-ment lying side-by-side, and having friends and co-workers walk down the line picking up one of each page I'm sure most readers have done this at least once in their lifetimes Collating settings and devices are great time savers

collect callAcall, usually on the telephone, in which the receiver pays for the call once it has been initi-ated Most collect call systems require the prior ap-proval of the person receiving the call before the call

is pennitted to continue Person-to-person calls are generally more expensive than station-to-station calls

It is more difficult now to connect collect calls, as many people have answering machines to screen calls, and may not hear the operator requesting au-thorization

collimatelJ.To make parallel, to cause to follow par-allel trajectories See coherent

collimation 1 The process of making something travel parallel, with a minimum ofdivergence or con-vergence 2 The process ofmaking light waves travel parallel without diverging or converging This pro-cess is useful in testing and aligning optical instru-ments and is essential for technologies that require a coherent beam that doesn't significantly lose power over distance due to spreading or scattering collisionIn data networks, there are commonly many

Fiber Optics Illustrated Dictionary

devices trying to send signals at the same time Ifthis

happens at exactly the same time, collisions may

oc-cur There are a number of mechanisms to manage

collision-detection and traffic flow, includingjam

sig-nals for preventing simultaneous transmissions

Typi-cally, the jam signals will cause devices to back off

and wait for a random period of time before trying

again The introduction ofthe random time factor

re-duces the chance of the same devices starting the

transmission again at exactly the same time Care

must also be taken to ensure that not too many

colli-sions occur Ifthere are many collicolli-sions, and devices

are constantly backing off and trying again, then

throughput may be compromised Excessive

colli-sions may mean that an additional router or bridge

needs to be added to the system or that some devices

need to be disengaged

collision detectionOn data networks, the means by

which the system detects that more than one device

is attempting to transmit data at the same time This

detection may be done in a number ofways, with

ac-knowledgments being one means of signaling a

sys-tem that data has made it successfully through If it

hasn't, and no acknowledgment is received in a

rea-sonable amount of time, then there may have been a

collision and the system reacts accordingly One type

ofmechanism triggered by collision detection is ajam

signal, which alerts devices to back off until the jam

is cleared See collision, jam, jam signal

collocation1 Adjacent placement 2 Physical

place-ment of customer transport and/or multiplexing

equipment within the carrier's premises

collodionAviscous solution introduced into the

pro-cessing ofphotographic prints in the 1850s

color burst.See burst

color carrier referenceAcontinuous signal, related

to a color burst signal, used for modulation and

de-modulation

color codeAnidentification system based upon

col-ors or specified widths or patterns ofcolor Many

in-dustries color code their dials, wires, and components

for quick recognition and selection Electronic

com-ponents such as resistors are often labeled as to their

values with bars of colors in particular sequences

Color Graphics AdapterCGA A color graphics

standard introduced by International Business

Ma-chines(ffiM)in 1983 as their first color graphics

con-troller card Until then, ffiM computers with native

controllers displayed only in monochrome CGA

sup-ported a display resolution of320 x 200 It has since

been superseded, first by EGA, and then by VGA,

and now, almost entirely by SVGA

color modelAconceptual description of how colors

are detected, perceived (usually by humans), or

re-produced Human color perception is an exquisitely

sophisticated phenomenon, as is described

insightfully and anecdotally in Oliver Sacks' An

Anthropologist on Mars.Many, many color models

ex-ist' none of which is complete or generalizable to

every situation See CMYK., color space, Maxwell's

triangle, Munsell's color model, RGB

color monitorA monitor that uses color transistors

or LEDs or is coated on the inside front of the tube with phosphors which when excited glow in particu-lar colors (usually red, green, and blue), which com-bined can appear as any of millions of colors Red, green, and blue are considered primary colors in light, because their combination in different intensities pro-duces virtually any color (Pigment systems define red, yellow, and blue as the primary colors.) Thus, most color systems in cathode-ray tubes employ three electrongunsand are commonly known as RGB systems color spaceA model or scheme for objectifying the representation ofcolor Many color spaces exist, most

of them devised to work with specific technologies Color spaces for printing pigments assign numeric values to particular hues which are further coded so that the printer can mix the correct inks for use on the press

color subcarrierA monochrome broadcast signal that is modulated with sideband information in or-der to convey color

color television standardsDifferent parts of the world have standardized on different formats and even different subformats, many of which are not intercompatible The common ones for color televi-sion are NTSC, PAL, and SECAM

colorimeterAnoptical instrument for measuring and comparing colors from different sources, often used

to match or calibrate colors according to a color model or sample

colorimetryAquantitative method ofspecifying col-ors through attributes such as wavelength (color), excitation purity (saturation), and luminance (intensity) Colossus Mark IA code-breaking machine devel-oped by Alan Turing and others, put into service in

1944 in Bletchley Park, England, to help decrypt messages from other nations, particularly Germany, transmitted during World War II It was delivered under the leadership ofTom Flowers, representing the Telephone Research Establishment; Max Newman and Harry Hinsley played prominent roles The ex-istence ofthis machine was not publicly known until almost three decades later See Manchester Mark I; Turing, Alan

COLPconnected line identification presentation (e.g., as in ISDN Q.81 and Q.731 number identifica-tion services)

COLRconnected line identification restriction (e.g.,

as in ISDN Q.81 and Q.731 number identification services)

Columbia Broadcasting SystemCBS This major U.S network was granted its fITst commercial broad-cast license in 1941 and not long after began to de-velop a color television system

COM 1 See Component Object Model 2 See con-tinuation of message

Com21,Inc Apublicly trading American-based glo-bal ISO 900 I-registered supplier for the broadband access market, founded in 1992 The company pro-vides ATM, nOCSIS, and EuroSIS products to cable service providers and operators for delivering high-speed Internet and telephony applications Com21 has

a research facility based in Ireland

a range of frequencies, usually UHF, VHF, and FM,

in a single unit Combination antennas have a

vari-ety ofelements including reflectors, Yagi-Uda arrays,

and log-periodic components to accommodate a

va-riety of signals with good gain Since several signals

are being received, the down-lead will usually require

a splitter to feed the individual signals into the

ap-propriate components, or in a combination

compo-nent, into the appropriate input receptacles See

an-tenna, UHF anan-tenna, VHF antenna

COMETTCommunity Action Programme in

Edu-cation and Training for Technology.Aninitiative of

the European Union

Comisi6n de Regulaci6n de Telecomunicaciones

CRT The telecommunications regulatory

commis-sion of the Republic of Columbia

http://www.crt.gov.co/

Comisi6n Federal de TelecomunicacionesCofetel

Anadministrative agency of the Secretary of

Com-munications and Transportation of Mexico

http://www.cofetel.gob.mxI

Comisi6n Nacional de ComunicacionesThe

na-tional communications commission of Argentina

http://www.cnc.gov.ar/

Comisi6n Nacional de Telecomunicaciones

CONATEL The national telecommunications

com-mission of Honduras http://www.conatel.hn/

Comite Consultatif International Telegraphique

et TelephoniqueCCITT This important standards

body is now known as the lTU See ANSI, CCITT,

International Telecommunication Union

command bufferA portion of memory that stores

recently executed commands or frequently executed

commands, so that the command can quickly be

fetched and re-executed if needed A buffer is a type

of simple memory cache used to speed up the

over-all performance of a system See cache

command line interface, command line interpreter

CLI The software interpreter that accepts text

com-mands input by the user, attempts to fulfill the request

by interpreting them into machine language, then

re-sponds with an answer, information, or error message

Most operating systems come standard with a

com-mand line interpreter; the Macintosh is a notable

ex-ception On many computers, such as Amiga and

Unix systems, new commands can be readily added

to a bin directory and henceforth executed in the same

manner as the default command set See command

line

command pathAlocation designator for directories

on a system that hold system commands or

com-mands that are to be activated from anywhere on the

system without having to type the full path from the

current directory Most systems have a configuration

file that allows common path names to be established

at start-up time, and these generally stay active while

the system is powered up Ifpath names are changed,

it will be necessary to reread the path file to

estab-lish the new paths and, on some systems, you may

have to reboot the machine (very inconvenient)

Commercial Cable CompanyAhistoric

communi-Mackay and James Gordon Bennett, Jr The company laid some of the earliest cables between Ireland and the west coast of North America, and later to conti-nental Europe as well The company was hotly com-petitive with Western Union but needed land systems

to be completely independent of Western Union As

a consequence, Mackay purchased a controlling share

of Postal Telegraph Company

Commercial Internet ExchangeCIE.Analliance

of CERFnet, UUNET, and PSI in 1991 Since that time, other services have fonned agreements with CIX to allow unrestricted flow of traffic across net-works in the CIX backbone For a fee, service provid-ers may access and send traffic across the network Commercial Internet Exchange AssociationCIX

A nonprofit trade association established to promote and support the use of the Internet for commercial activities Its members consist of public data inter-network service providers supporting public data communications CIX provides a forum for the ex-change ofideas and information and encourages tech-nical research and development Membership is open

to organizations offeringTCP/IPor Open Systems Interconnect (OSI) public data intemetworking ser-vices to the general public http://www.cix.org/ Commercial Space Launch Act of 1984AU.S act

of Congress that provided support for private satel-lite communications systems launching and opera-tion The regulation at present is light, mostly related

to Federal Communications Commission (FCC) fre-quency assignments and the positions of satellite or-bits, but this situation may change in the decades ahead as more and more satellites vie for space in Earth orbit See Telecommunications Act of 1996 committed burst sizeBe See burst size, committed committed information rateCIR Aservice rate and traffic flow commitment level established for service

in a Frame Relay network That is, the CIR is a level that is agreed upon for data transmission rates The user may use higher transmission rates, but the ex-cess data will be marked as discard eligible (DE) in the case ofnetwork congestion Since rates may vary,

it is a computed average over a specific period of time See cell rate

committed rate measurement intervalTc In net-working, the nonperiodic time interval used to mea-sure incoming data, during which the user can send

only committed burst size committed amount ofdata and excess burst size excess amount of data Gener-ally, the duration ofthis measurement interval is

pro-portional to traffic burstiness See committed infor-mation rate, committed burst size

Committee TlAn ANSI-accredited organization established in 1984 that develops and publishes U.S network reliability standards and technical informa-tion ofinterest to network equipment developers, in-stallation and maintenance personnel, and system ad-ministrators The organization contributed to the lTU-T I-series recommendations for B-ISDN among others

Documents related to safety, power, ISDN, SONET,

Fiber Optics Illustrated Dictionary

SS7, and wireless communications are available

through Committee TI 's sponsor, the Alliance for

Telecommunications Industry Solutions (ATIS) in

Washington, D.C Committee T1 works in

coopera-tion with organizacoopera-tions such as the Network

Reliabil-ity Council See Alliance for Telecommunications

Industry Solutions http://www.tl.org/

Committee Tl Technical Reports The Committee

T1 provides a series of telecommunications

techni-cal documents available for a fee, and some that can

be freely downloaded off the Internet in Adobe

Post-Script or Adobe Portable Document Fonnat (which

can be read with one of the many freely distributed

Adobe PDF readers) Abstracts for Approved ANSI

TI Standards are also available Since many of these

are of direct interest to people developing, installing,

and maintaining communications networks, a few are

listed in the Committee T1 Technical Report

Ex-amples chart

Commodore 64 computer C64 A low-cost 8-bit

computer introduced by Commodore Business

Ma-chines in the early 1980s, aimed at the home and

school markets Listed at under $600 U.S., the C64

included a 6510 CPU with 64KRAM, a built-in sound

generator, the Digital Research CP/M operating system,

and game controllers and cartridge slot Itfeatured

320 x 200 pixel color graphics, was competitive with

the Apple IIe (48K) and the Atari 800 (16K), and

con-tinued to be popular for a couple of years after the

Amiga was introduced by Commodore in 1985 The

CI28 was an expanded version of the C64

Commodore Amiga See Amiga computer

Commodore Business Machines CBM Fonnerly an

office equipment company selling calculators and,

later, the Commodore PET (Personal Electronic

Transactor) computer, CBM is now best remembered

for its introduction of the Amiga computer In the

mid-1980s, when Radio Shack had lost its enonnous

market share to IBM computers, Commodore acquired

a computer named the Lorraine and launched it in the

Fall of 1985 as the Amiga (despite protestations from

its developers that the operating system (OS) wasn't finished and that the hardware should have slots and more memory) Due to problems in management and marketing, CBM or Commodore-Amiga, as it came

to be known, folded,with the Amiga assets bought out

by a Gennan company and later sold to Gateway, Inc Licensing use was subsequently sold to Amino De-velopment Corporation, now Amiga Corporation (though Gateway retained ownership of the patents) Commodore folded in 1994, but the Amiga didn't Developers' conferences were reinstituted in 1997 and the Amiga2001 show was held in St Louis in March 200 I See Amiga computer; Apple Comput-ing; Miner, Jay

Commodore PET Personal Electronic Transactor One of the earliest commercially successful micro-computers, the PET was introduced early in 1977 by Commodore Business Machines.Itwas competitive with the Tandy Radio Shack TRS-80, which initially was also black and white with 4 kilobytes of RAM, but both computer systems were eventually overshad-owed by Apple and IBM computers

Common Applications Environment CAE Aset of standards intended to provide a framework for inte-grated systems, developed by the X/Open Company See Single UNIX Specification

Common Architecture for Next Generation Inter-net Protocol CATNIP When IPv6, the successor to IPv4 for the Internet, was in the design stages, a num-ber of proposed fonnats were submitted CATNIP is one of three fonnats that were incorporated into the IPv6 specification by the Internet Engineering Task Force (IETF) See IPv6

common batteryInearly telephone central offices,

a 24- or 48-volt battery called a talking battery was

used for supplying the power for a phone conversa-tion Later, starting around 1893, these were replaced

by 48-volt common batteries at the central office

which supplied the talking battery to each subscriber through the wireline, rather than each subscriber individually providing battery power This practice

Committee Tl Technical Report Examples

TR-7 June 1986 3-DSO Transport of ISDN Basic Access on a DS I Facility

TR-13 Dec 1991 A Methodology for Specifying Telecommunications Management Network

Interface TR-15 March 1992 Private ISDN Networking

TR-21 Sept 1993 System and Service Objectives for Low-Power Wireless Access to Personal

Communications TR-36 May 1994 A Comparison of SONET and SDH

TR-45 Dec 1995 Speech Packetization

TR-47 June 1996 Digital Subscriber Signaling System Number I (DSS I) - Codepoints for

Integrated Services Digital (ISDN) Supplementary Services TR-53 June 1997 Transmission Performance Guidelines for ATM Technology Intended for

Integration into Networks Supporting Voiceband Services

signed See battery.

common bell A bell that rings when any of the

des-ignated lines on a phone system ring.Itis often

stalled on main consoles, to allow an operator to

in-tercept calls, or on night systems, so a single person

can answer calls on several lines that would normally

be answered individually

common carrier A public communications service

carrier, usually regulated and licensed by agovernment

agency Acommon carrier may not withhold service

or discriminate against any public purchaser of the

services

Common Carrier Bureau CCB Alarge department

of the U.S Federal Communications Commission

(FCC) that recommends and implements regulatory

policies for interstate telecommunications through

en-forcement, pricing, accounting, and program planning

of network services and wireline services

Common Channel Interoffice Signaling CCIS.An

out-of-band telecommunications signaling system

that encodes information and sends the signaling data

over channels separate from the voice signals, using

digital time-division multiplexing (TDM) This

sys-tem is more efficient - full voice-grade paths are not

needed for sending signaling information - and more

secure than older signaling systems which used 2600

and 3700 Hz tones as supervisory signals

Some of the key points in CCIS networks include

Signal Transfer Points (STPs), tandem switches

act-ing as routers, Signal Control Points (SCPs), data

application servers, and Service Switching Points

(SSPs) capable of switching tens of thousands of

in-dividuallines

CCIS was introduced by AT&T in 1976 The system

was significant in that it introduced a new out-of-band

network, separate from the network carrying the voice

conversations, for the telephone signaling

transmis-sions This type of system was inherently more

se-cure than an in-band signaling system using tones that

could potentially be introduced into the circuits by a

user The CCIT adopted CCIS as an international

standard called Common Channel Signaling System

7 (CCS7 or more commonly now SS7) See

Signal-ing System7

Common Channel Signaling CCS CCS is a system

that developed as local telephone carriers gradually

linked up with regional systems, necessitating some

common signaling standards for compatibility

Tele-phony required the transmission of two general

categories of data, the informational content of a

phone conversation and the supervisory/control

sig-nals associated with establishing, maintaining and

disconnecting the calls

As touch-tone technology developed and gradually

superseded pulse dialing, and digital systems

gradu-ally emerged, the sophistication of the types of

sig-naling that could be carried over phone lines

in-creased New services were devised that took

advan-tage of digital signaling (e.g., Caller ID)

Originally both the signaling and the conversations

were carried on the same channel However, the

blue-vealed significant security weaknesses in this method, and out-band signaling took precedence, with con-tent and supervisory data carried on separate chan-nels (In-band signaling still exists on many local branch systems but metropolitan and national

mentations, the signaling and call content had to be interleaved rather than overlapped, a situation that limited the types of information that could be trans-mitted about a call while it was in progress (think of the difference between a single-tasking operating system and a multitasking operating system on a com-puter to get the general idea) CCS permitted some

of these limitations to be overcome, and it began to

be more widely implemented in the early 1990s

Thus, in ATM networks, CCS is a packet-based sig-naling architecture in which circuits share sigsig-naling channels in which the administrative and content sig-nals may be transmitted at the same time (i.e., you can read data about a call on an appropriate device while the call is in progress) CCS channels may be cross connected

CCS uses parameters that set up the network configu-ration, such as the switch type, debug level, data in-version mode, correspondence between maps and network interfaces and signaling instances, layer ac-tivation and timers, and data link flags

In Transparent Common Channel Signaling (T-CCS), private branch exchanges can be interconnected with digital interfaces that use non-CCS protocols (e.g., a proprietary protocol) without the CCS signal having

to be interpreted to process calls on the system The proprietary signaling is preserved and transported transparently through the data network through a point-to-point connection In other words, instead of routing the transmissions, a preconfigured route is used in conjunction with CCS frame forwarding to support transparency

CCS has been defined for use with Signaling System

7 (SS7) telephony CCS facilitates the establishment and take-down of calls, signal monitoring, internet-work transmissions, and special-case call handling (e.g., calling card connections) See Signal Transfer Point, Signaling System 6, Signaling System 7

Common Channel Signaling Task Force One of a

number of task forces of the Presidential National Security Telecommunications Advisory Committee (NSTAC) that looked into matters such as security

of the public telephone network, in the early 1990s, and issued a Final Report in Jan 1994 In May 2000, NSTAC issued a report on information technology (IT) telecommunications convergence issues for na-tional security and emergency preparedness (NS/EP)

Common Desktop Environment CDE An

inte-grated graphical user interface for open systems fea-turing a standard interface for management of data and applications CDE is an IETF platform Human Computer Interface (HCI) standard See X Window System

Fiber Optics Illustrated Dictionary

Common Gateway Interface CGI Ameans

ofcom-municating instructions to a Web server through

scripts or code, in order to enhance the utility ofWeb

pages HTML, a markup language used on the Web,

was designed for formatting, not processing, data

in-teractions To extend the utility of HTML, the CGI

can be used in conjunction with input to Web pages

to process forms, messages, chat room interactions,

database records, searches and more Perl is one of

the most flexible, powerful, and prevalent languages

for implementing CGls on the Web, especially for text

processing, database searches, and fonns parsing Sun's

Java tends to be used in situations where graphical

menus, games, or images are desired See ActiveX,

Java, Perl

Common Intermediate Format CIF A subsection

of the lTU-T H.261 standard that specifies various

broadcast format parameters for ISDN

videoconfer-encing See ISDN See Common Intermediate

For-mat Types chart

Common Location Language Identifier CLLI A

unique identifier system, developed by Bellcore, for

certain regions and equipment Thus, various

ex-changes, buildings, and facilities could be coded A

CLlI consists offoUT characters for the location,

fol-lowed by two characters for the region, and five

char-acters for the item

Common Management Information Protocol

CMIP A standardized connection-oriented network

management protocol based upon the Open Systems

Interconnection (OSI) model CMIP supports

infor-mation exchange (as opposed to network

functional-ity) between network management applications and

management agents through managed objects CMIP

is part of the X.700 Recommendation of the lTU-T

(also ISO/IEC 7498/4) CMIP was designed by

in-dustry and government participants to be the heir to

the simpler Simple Network Management Protocol

(SNMP) CMIP supports security features, including

access controls, activity logging, and authorization

It works in conjunction with the Common

Manage-ment Information Service (CMIS), which defines

services for accessing information about network objects or devices

A number of vendors have implemented CMIP For example, Solstice CMIP has been developed to pro-vide CMIP services on Sun Microsystems' Solaris 64-bit platform In the early 1990s, AT&T and NCR released StarPRO CMIP compatible with BaseWorX UNIX-based systems See Common Management Information Services

Common Management Information Services CMIS A standardized network services mechanism

to enable peer processes to exchange information and instructions through a defined message command set CMIS works in conjunction with Common Manage-ment Information Protocol (CMIP) The CMIS Y.2 definitions and protocol were described in ITU-T X.710/711 Recommendations in 1991 CMIS was standardized in the mid-1990s as ISO/IEC 9595/2

In 1997, S Mazumdar ofBell Labs proposed a set of extensions that defined interfaces for providing CMIS-based services using the Object Management Group (OMG) object services such that CMIS-based objects could be made compatible with other man-aged objects in a native Common Object Request Broker Architecture (CORBA) environment Common Management Information Services and Protocol over TCPIIP CMOT CMOT is an Inter-net Protocol information service mechanism in the context of ISO-standardized Common Management Information Services/Common Management Infor-mation Protocol (CMIS/CMIP) as it applies to a TCP/IP environment CMOT was submitted as an RFC by Warrier and Besaw in April 1989 and updated October 1990 as a move toward international stan-dards suitable for implementation over the evolving Internet

CMOT provided a means for implementing the Draft International Standard version of CMIS/CMIP over Internet transport protocols in order to carry manage-ment information See Common Managemanage-ment Infor-mation Protocol See RFC 1189 (which obsoletes RFC 1095)

Common Intermediate Format (CIF)Types Format LinesxPixels Defined within Standard Notes

ClF, FCIF,andQCIFstandards, sometimes collectively calledp*64.

CIF 352x288color H.261 Suitable for large format videoconferencing

Requires twoBchannels to support both audio and video

H.221, H.230, H.242 Communications, control, and indication

H.711, G.722, G.728 Audio signals

-QCIF 176x144 H.276 Requires less bandwidth than CIF but also

provides less resolution

ATM networking, a portion of the convergence

sub-layer ofan ATM adaptation sub-layer (AAL) that remains

common to different types of traffic

common part indicator CPI In ATM networking,

a I-byte field used to interpret the remaining fields

in the header and trailer

Common Object Request Broker Architecture See

CORBA

Common Open Policy Service Protocol COPS A

simple, extensible client/server protocol model for

supporting policy control over quality of service

(QoS) network signaling protocols COPS is a query

and response protocol that enables policy

informa-tion to be exchanged between a policy server and its

clients (e.g., RSVP router) See RFC 2748

Communications Act of 1934 A U.S federal

regu-lations act to organize and promote competitive

com-munications technologies and services This act

es-tablished and described the responsibilities and

ju-risdiction of the Federal Communications

Commis-sion (FCC) which was descended from the Federal

Radio Commission (FRC) formed from the Radio Act

of 1927

The Communications Act of 1934 was amended by

the Omnibus Budget Reconciliation Act (OBRA) to

preempt state jurisdiction in such a way that

indi-vidual states were no longer regulating rates and

en-tryby companies offering wireless services It

fur-ther organized wireless into two categories:

commer-cial mobile radio services (CMRS), including

cellu-lar radio services and personal communications

ser-vices (PCS), and private mobile radio serser-vices

(PMRS), including public safety and government

services

Communications Act of 1996 See

Telecommunica-tions Act of 1996

Communications Applications Specification CAS

A communications protocol developed in the late

1980s by Intel and Digital Communications

Associ-ates, Inc (DCA) for use with computer peripherals

to enable software to communicate with fax/modem

interfaces This protocol, along with Class 1, 2, and

3 fax standards, helped standardize computer

fac-simile communications, enabling software from

dif-ferent vendors to exchange data

Communications Authority of Thailand CAT A

state initiative under the Ministry of Transport and

Communications, established in February 1977 CAT

is responsible for a national communications network

linking to the global community http://www.cat.or.th/

Communications Decency Act of 1996 Aprovision

of the Telecommunications Reform Act that aroused

extreme controversy and opposition by the Internet

community as it made it a federal crime to send

cer-tain lewd, indecent, or other objectionable

commu-nications across networks The Internet community

rallied against it and, in a June 1997 milestone

deci-sion in the case of Reno versus ACLU, the act was

declared an unconstitutional violation of individual

rights to freedom ofspeech See Telecommunications

Act of 1996

Formerly the Telecommunication Managers Associa-tion, the CMA is a charitable business communica-tions trade association based in the U.K The CMA supports the role of managers in communications fields by providing and promoting educational activi-ties and excellence in the use of communications technologies http://www.thecma.com/

Communications Policy Project CPP A nonparti-san initiative ofthe Benton Foundation to strengthen public interest and participation in the shaping ofthe National Information Infrastructure (NIl) The Benton Foundation seeks to promote the use ofcom-munications for the greater social good and encour-ages democratic participation in policy debates and regulatory activities, especially those relating to open access to communications technologies and the pro-motion of diversity in services beyond the obvious commercial applications

Since the mid-1990s, a portion of the Foundation's efforts has gone into educating the public about new digital environments and broadcasting media and the importance of the equitable allocation ofradio spec-tra for positive social programming

Among other things, the CPP advocates support for low-power television (LPTV) stations, as these pro-vide diversity and a large proportion of social and educational content Many LPTV stations broadcast local news and proramming for hobby, church, ath-letic, and community groups LPTV stations often broadcast to remote or small communities that are not ofcommercial interest to large corporations because they don't have sufficient subscribers to generate a profit There is a persistent danger that LPTV services can be crowded out by commercial interests with strong lobbies and economic bases ifthey are not ac-tively protected and promoted by the public, the gov-ernment, and communications agencies such as the Federal Communications Commission See Benton Foundation, Community Broadcasters Association, National Public Radio, Public Radio International Communications Research Centre CRC A major communications research agency ofIndustry Canada located at a secure site near Ottawa, Ontario adjacent

to the Defence Research Establishment Ottawa (DREWO) and the Canadian Space Agency The CRC engages in collaborative, innovative research

in information technologies, communications, and broadcasting in support of Canadian knowledge-based economies It further provides an independent voice for public policy development

Communications Security Establishment CSE A Canadian federal agency for providing information technology (IT) security solutions to the Canadian government http://www.cse.dnd.cal

Communicatorill AnffiM-licensed/Intel-based PC videoconferencing product with audio, video, white-board, and file transfer capabilities from EyeTel Com-munications, Inc Communicator III works over Switched 56, ISDN, TI, Ethernet, and Token-Ring networks It uses ITU-T H Series Recommendation standards and encoding

Fiber Optics Illustrated Dictionary

Communique! A Sun SPARC-based

videoconfer-encing program from InSoft that works over ISDN,

FOOl, SMDS, Ethernet, ATM, and Frame Relay

net-works It supports audio, visual, whiteboarding, file

transfers, and a number ofapplications CellB, JPEG,

and Indeo standards and encoding are supported

Community Broadcasters AssociationCBA AU.S

national professional organization devoted to

support-ing and enhancsupport-ing diversity and vitality in the

com-munity broadcasting field, with a special interest in

Class Aand low-power television technologies which

are widely used in niche market and local

commu-nity broadcasting The CBA sponsors online news,

workshops, and provides input into government

poli-cies See Communications Policy Project,

Commu-nity Broadcaster's Protection Act, low-power

televi-sion, WorldAssociation ofCommunity Radio

Broad-casters

Community Broadcaster's Protection ActA

por-tion of the Omnibus Appropriapor-tions Bill signed into

law by President Clinton in 1999 as a direct result of

lobbying by the Community Broadcasters

Associa-tion The Act established a new class of television

broadcasting in the U.S., making it possible for

low-power television (LPTV) broadcasters to apply for

permanent status The CBA subsequently sponsored

seminars to help educate broadcast companies and

individuals on the implications and implementation

ofthe terms ofthe Act and aided them in

understand-ing Class A Compliance issues

In January 2000, the Federal Communications

Com-mission (FCC) adopted the Class A Notice of

Pro-posed Rule Making (NPRM) Three months

follow-ing,itreleased a report and order establishing the

Class ATelevision Service, followed by a list of

sta-tions considered to be eligible for this Service See

Communications Policy Project, Community

Broad-casters Association

Community Broadcasting Association of

Austra-lia CBAA The national representative body for

com-munity broadcasters in Australia The CBAA

pro-vides representation, education, and support for

li-censed stations and licensee hopefuls including

in-formation about issues, ethics, intellectual property,

fundraising, and Broadcasting Services Act

require-ments The CBAA hosts the national community

ra-dio satellite service See Community Broadcasting

Foundation http://www.cabb.org.au/

Community Broadcasting Foundation Ltd.CBF

Anindependent nonprofit funding body for

commu-nity broadcasting in Australia, established in 1984

The CBF is supported by the Australian Dept of

Communications, Information Technology and the

Arts (DCITA), and the Aboriginal and Torres Strait

Islander Commission (ATSIC) It solicits funds and

distributes grants for ethnic community broadcasting,

print handicapped broadcasting, general community

broadcasting, and policy development projects See

Community Broadcasting Association ofAustralia

community dial officeCOO A type of central

tele-phone switching office that is most often found in

small rural communities It is an unattended

switch-ing center that is serviced only as needed and main-tained on an occasional basis by a traveling mainte-nance technician

community radioA radio broadcast system that serves the cultural, ethnic, local news, special inter-est, or social needs of a community Community ra-dio stations are important because they are often the only venues for minority populations or isolated in-dividuals to access programming matching their needs and interests Many small groups are not served

by large, for-profit broadcast corporations Since most community radio stations are low-profit or no-profit" ventures, they do not have the same lobbying power with Congress or the Federal Communications Com-mission as large, powerful broadcasting conglomer-ates It is therefore up to listeners, foundations, edu-cators, and related organizations to support the vital role played by community radio in safeguarding free-dom of information and diversity

The growth ofthe Internet and the capability ofserv-ing streamofserv-ing audio to millions oflisteners has broad-ened the reach ofcommunity radio broadcasting and the concept of community While still not a profit venture in most cases, community radio stations can now broadcast to a wider spectrum of communities, based not just on geographical regions through low-powered transmitters, but to the entire world, through Web sites that can be accessed long distance without additional fees by all interested listeners with Inter-net access See Community Broadcasters Assocation, National Public Radio, People's Communication Charter, World Association of Community Radio Broadcasters

Community Radio Charter for EuropeA set of priniciples and goals adopted by AMARC at the Pan-European Conference of Community Radio Broad-casters in September 1994 The Charter recognizes community radio broadcasting as a vital medium for fostering freedom of expression and information, cultural freedom and diversity, and local culture and traditions It defines ideals and objectives to help ra-dio stations achieve these goals See World Associa-tion ofCommunity Radio StaAssocia-tions compact discA small, flat, circular, optical, digital random-access storage and retrieval medium CDs are written and read with laser devices CDs are used for audio recordings, audio/visual sound and graphics, and computer data and multimedia applications The CO format has been standardized to 120 mm (4.75") diameter It consists ofa thin layer of metal-lic film, etched with microscopic indentations called

pitsspiraling literally for miles around the recording surface This structure is coated with a smooth plas-tic surface The data is stored in a format that was developed by Sony and Philips and agreed upon by electronics vendors in 1981

CD players first began to be marketed in Japan and Europe, and to a limited extent in Canada, in 1982 They did not begin to be distributed widely in the United States until 1983 By 1986, consumer play-ers were inexpensive enough to promote an explo-sion of interest in audio CDs See SPARS code

stereo audio

sion of CD fonnats with read-only players based

around Motorola 68000 technology.Itwas developed

by Sony and Philips and released in 1988 CD-I

al-lows interactive multimedia use of compact discs

The CDs can be recorded with infonnation in

vari-ous fonns, including computer data files, video

im-ages and still frames at more than one resolution, and

audio in three fonnats

Compact Disc Player - SCSI Connection

The back andfront ofa NEe external compact disc

drive (CD) showing the various selectors, connectors,

and components Internal CD drives usually dont

re-quire disc caddies.

compact disc types and uses The two most common

types of CDs are music CDs and multimedia

com-puter application CDs Music CDs are supplanting

music on cassette tapes and vinyl records due to the

greater clarity ofthe sound (no scratches or hiss) and

greater stability of the medium (magnetic data, and

the thin tapes themselves are somewhat fragile)

CD-ROM discs hold about 680 MBytes of data,

al-though actual infonnational content may be greater

if the data has been compressed

Typically, CDs are written once and read many times,

although the data on PhotoCD discs may be extended

in several sessions, with the new data being

writ-ten to an unused section of the disc.Amultisession

CD player is needed to read discs that have been

re-corded in more than one session See bar code,

com-pact disc; digital video disc, laserdisc, PhotoCD

compact disc video CD-Video Avariation on

com-pact disc technology, announced in 1987, which

de-livered audio and video on one disc The inner

por-tion of the disc is the recorded music and the outer

portion contains up to about five minutes of analog

video and sound, similar to a small laserdisc CD

faster than when playing the standard audio track on the inner portion of the disc

compander A transmission device that compresses and expands a signal, usually to save transmission

time Modems that use compression techniques on-the-fly are companding devices and are typically in-stalled at each end ofa transmission line

companding A combination and telescoped word

derived from compressing and expanding

Compand-ing is a process of compressCompand-ing and expandCompand-ing a sig-nal and is used for a variety of purposes, including noise reduction, security, and increased transmission speed

Compaq Computer Corporation Asuccessful com-puter company established in 1982 Compaq shipped its first product a few months later, in January 1983, achieving phenomenal first-year sales Compaq made the Fortune 500 list in 1986 It bought out Digital Equipment Corporation (DEC), one ofthe long-time, well-known companies in the computer industry, in

1998, and subsequently being bought out by Hewlett-Packard

Competitive Access Provider CAP A competitive local carrier that is pennitted to compete with Local Exchange Carriers (LECs) and Inter Exchange Car-riers (IXCs) to provide voice or data services See Competitive Local Exchange Carrier

Competitive Local Exchange Carrier CLEC A competitive carrier that is permitted to compete with established local voice and data service providers, as

a result of the deregulation in the Telecommunica-tions Act of 1996 CLECs may build their own wire-lines or lease existing wire-lines for resale of services CLECs include CAPs, IXCs, CATV service provid-ers, and others See Incumbent Local Exchange Car-rier

Competitive Telecommunications Association CAT ACanadian-based association representing new entrants in the telecommunications service business, including interexchange carriers (IECs), competitive access providers (CAPs), and resellers

complete document recognition CDR A process that goes beyond object character recognition (OCR),

in that it recognizes not only text and individual blocks or elements on a page, but the general layout and types ofdata CDR software is quite sophisticated and can fairly reliably distinguish the difference be-tween text and images, headlines and regular text, and columns and sidebars

completed call In the telephone industry, completed call has a fairly specific meaning, describing a call that has reached and been answered by the callee, but

itdoes not include the time that the callee actually spends on the conversation.Inother words, the

mean-ing of completed call concerns the establishment of

the connection with the person being called and not the actual length of the communication

complex instruction set computing CISC Amicro-processor architecture that accommodates complex machine language instructions in which a single operation may be comprised ofmany small instructions