Fiber Optics Illustrated Dictionary - Part 16 pps

C-band, opticalInoptical communications, an lTU-specified transmission band in the 1530 to 1565-nm range that is used for fiber optic transmissions and which recently is sometimes supple

Fiber Optics Illustrated Dictionary

productivity applications, demo programs, and clipart

libraries 2 Individual wires or cables combined or

interwoven to form a bundle for ease ofhandling and

installation

Bunsen cellAtype ofcell devised by R.W von

Bun-sen that was an adaptation of an early wet cell in

which the positive electrode was suspended in a bath

ofcontained nitric acid (separated from the outer

elec-trolyte solution) so that hydrogen would be oxidized

and the cell depolarized See dry cell; wet cell; von

Bunsen, R.W

buried cableAnunderground cable installation that

cannot be altered without disturbing the soil, or

ac-cessing the cable under the soil through some

en-trance point Buried cables are more aesthetic, as they

do not clutter the landscape with utility poles and

wires, but may be less easy to access to make changes

or repairs See Call Before Digging

burn-in Adiagnostic preliminary operation,

some-times at high temperatures, to test devices and

cir-cuits in order to identify those likely to fail In

elec-tronics, many problems will show up early, in the first

few weeks ofoperation, or under stress from heat and

humidity Sometimes called early failure period

burn-in, monitorAnundesirable ghost image on the

coating inside a cathode-ray tube (CRT) monitor

re-sulting from the persistent display of the same

im-age or similar imim-ages Monitor burn-in can be

pre-vented by turning the monitor off when not in use,

and using screen savers that darken the screen

com-pletelyor, second-best, that move around small,

low-contrast images Many commercial products called

screensavers do not save your screen If a bright, still

image covers most or all of the screen, it's not a

screensaver, no matter what it is called, and

persis-tent display of the image will cause burn-in

burnoutAcondition in which a person's physical and

psychological resources are severely depleted and

stressed, and there are insufficient resources (e.g.,

time) for the body/soul to repair and renew itself

Overwork over an extended period with frequent

stress-related deadlines usually leads to burnout

Burnout is prevalent in health professions where long

hours and stressful shift work are common and in high

tech startup companies where long hours and limited

venture financing create deadline pressures and

over-work

Symptomsvarybut may include lethargy, anxiety,

shivering, vertigo, headaches, migraines, stomach

upsets, insomnia, frequent colds, muscle aches,

chronic inflammation, and apathy Factors

contrib-uting to burnout can include oveIWork, lack of

vari-ety, low pay for the type of work done, lack of

ap-preciation, poor time management, lack of rest and

exercise, poor working conditions, long hours spent

with a demanding public (such as sales or

telesolicitation) See a health care professional ifyou

suspect burnout and consider some lifestyle/priority

changes

burn rateThe rate at which a seed or startup

com-pany uses its initial cash resources in the process of

developing and marketing a new product or service

with the goal ofmaking the company financially viable Bum rates for startup software development compa-nies, for example, are minimally three to four mil-lion dollars per year and up (for a small company of about five to thirteen employees) for the first couple ofyears and can be much higher for telecommunica-tions hardware development and manufacturing com-panies Occasionally software products will come to market for much lower cash investments, but this is usually in situations where the developers have day-time jobs and invest in the startup in terms of "sweat equity" (time invested) rather than cash

burn rate, employeeThe rate at which a company uses up its personnel resources in order to get the most productivity for the money paid in wages Some com-panies take advantage ofthe fact that people can work extra hours and put in extra energy over the short haul (e.g., up to about two years) See burnout

burst1 Sudden increase in signal strength See surge

2 A color burst, or reference burst, is an oscillator phase reference in a color broadcast receiver 3.In printing, the separation of continuous-feed or multi-part pages into individual sheets, usually along a per-foration See burster 4 In a Frame Relay network, a sporadic increase in a circuit where the total band-width is not continually in use 5.Indata communi-cations, a sequence of more-or-Iess contiguous sig-nals that are treated as a unit according to a predeter-mined set of criteria

burst error, burst noise1 A data burst sufficient to garble or interrupt data transmission For example, scratches may result in a burst error on a laserdisc, audiodisc or magneto-optical storage disc Some sys-tems have software error-checking which will mini-mize the negative effects of a burst error, or which will make a best guess as to what the data should have been 2 In audio transmissions, noise and interfer-ence that substantially exceed the ambient noise or the level ofthe desired transmission, e.g., sudden pops and clicks on an old vinyl recording

burst modeA data transmissions mode in which the data is sent faster than usual, sometimes due to a de-vice temporarily monopolizing the transmissions channel See caching

burst modemBM Amodem developed to send and receive information in bursts rather than as a continu-ous connection Burst modems are typically used in applications where bandwidth is at a premium or for connections that may be expensive Since many com-munications include blank spots or long pauses that eat up connection time, a burst modem can more ef-ficiently handle traffic on packet data networks, mul-timedia services, and consumer communications net-works (e.g., cell phones)

burst pressureThe maximum pressure that a device

or mechanism can tolerate before rupturing This phrase is often used in reference to liquid or vapor conductors

burst sequenceIn color video transmission, a mecha-nism for improving the stability of color synchroni-zation by controlling the polarity of the color burst signals

networking, a cell traffic descriptor for the maximum

amount ofdata (total number ofbits) that the network

will agree to transfer during a time interval Tc.Itcan

be set individually for virtual circuits (VCs) See cell

rate

burst size, excessBe, B In Frame Relay

network-ing, a cell traffic descriptor for the maximum amount

ofuncommitted data, in excess ofthe committed burst

size (Bc), that the network will endeavor to deliver

during a time interval (committed rate time interval

- Tc) This type ofdata is eligible for discard,

ifnec-essary, to provide quality of service (QoS) The

ex-cess burst size can be set individually for virtual

cir-cuits (VCs) Bursty traffic and congestion are two of

the common traffic management challenges that are

handled with a variety ofprocedures See cell rate

burst time intervalA calculated interval related to

signal bursts that is used to delineate a time period

for assessing traffic in a network.InFrame Relay

net-works, for example, throughput is evaluated to gauge

and adjust performance and user service levels The

committed rate time interval (Tc) is based on the

ra-tio ofcommitted burst size to committed (data) rate

burst transmissionA transmission in which the

sig-nal is intentiosig-nally sent in a group at significantly

higher speeds than is usual, with as much

informa-tional content as possible For example, in radio

trans-missions, the information may be sent in a burst at

50 or 100 times the normal speed and then played to

the listener at normal listening speeds Burst

trans-mission is a technique for getting more information

transmitted in less time

burst transmission, isochronousIn a data network,

where many different devices may be operating at

different speeds, burst transmission may be used to

resolve some of those speed (data rate) differences

in order to operate the network more efficiently

bursterInprinting, a device that speeds and

facili-tates the separation of continuous feed or multipart

pages into individual sheets, usually along a

perfo-ration This type of equipment is sometimes

incor-porated into a multiple-capability machine

(burster-trimmer-stacker) which also trims the pages to

re-move the tractor-feed strips and stacks the paper

bursty dataData that come in spurts; it is often

un-predictable The nature ofthe data is important in the

design ofnetwork traffic flow control procedures and

protocols See variable bit rate

bursty informationInformation that alternates

be-tween intervals of low transmission and short bursts

ofhigh transmission incorporating a lot ofdata Print

jobs tend to be bursty, with long periods of idleness

and short periods where it seems as if everyone on

the network submits a job to the print queue at the

same time (e.g., just before lunch break)

bus1 An uninsulated conductor, such as a wire, bar,

or printed metal patch on a circuit board, intended to

provide an electrical contact point for adjoining

con-ductors or devices Commonly used in telephone and

computer circuits See backplane, edge connector,

ex-pansion slot 2 A category of standards that

facili-consumer electronics products 3 One type of com-puter architecture in which a series of comcom-puter pro-cessing units (CPUs) are interconnected 4.Inits most basic sense, an uninsulated solid or hollow conduct-ing bar or wire

BUS See Broadcast and Unknown Server

bus, dataThe data pathways internal to a computer that permit the transfer ofdata within the system and

to peripherals associated with the system Common buses include address and data buses which mayor may not match the capacity ofthe CPU Bottlenecks are possible at the bus ifthe information reaching the bus is greater than its physical or logical carrying ca-pacity (e.g., a 16-bit address bus on a 32-bit CPU) Bus Interface Gate ArrayBIGA A Cisco Systems technology for allowing a Catalyst 5000 to receive and transmit frames from the packet-switch memory

to the Media Access Control (MAC) local buffer memory, independently of the host processor bus masteringA capability ofa peripheral device to take over functions and transfer data through a computer's system bus This capability is incorpo-rated into PCI video cards, for example, so the card can directly access system memory and provide other performance improvements Bus mastering is a means of direct memory access (DMA) processing bus topologyAnetwork topologyinwhich individual nodes are connected to a single communications line which is terminated at either end Like a ring topol-ogy, this arrangement is fragile in that if one node or system goes down, it affects the entire network See star topology, topology

Bush, Vannevar(1890-1974) An American engineer and writer who devised the product continuous integraphorproduct integraphinthe mid-1920s This device was a semiautomatic machine for solving problems He later invented thedifferential analyzer,

an evolutionary descendent of the integraph, a me-chanical apparatus for solving problems Bush was President of the Carnegie Institution of Washington from 1939 to 1955

bushing1 Acylindrical lining in an opening/hole that aids in controlling the size of the hole, insulating it

or providing a path, as for wires See ferrule 2 A cy-lindrical utility pole insulator with external ribs at one end This type ofinsulator was typically used on high voltage leads

busy1 A system that is in use For example, a printer may be busy processing data or handling a current job and thus is unable to process incoming data Thus,

it may buffer the data or send a busy signal to the sending station 2 A telephone that is in use or off-hook and unable to receive calls, or a telephone trunk that is at capacity and can't finish processing the call See busy signal, fast busy

busy backA signal that communicates the call sta-tus back to the caller See busy signal

busy hourThat hour during a specified period (day, week, etc.) in which the greatest volume of traffic is carried, as on a phone or computer network Busy hour traffic volume and characteristics provide

Fiber Optics Illustrated Dictionary

important data about the capacity, equipment, and

switching needs of a network The busy hour

char-acteristics can be used to determine the amount of

variation from low to peak usage times, the expected

maximum requirements of the system, and other

ad-ministrative and operational parameters On phone

networks, busy hour times have changed (become

later in the day), probably as a result of the greater

use ofoff-peak hours for facsimile transmissions and

Internet usage

busy lamp, busy light A lighted indicator on a

de-vice that shows it is currently active, or in use The

busy lamp is often paired with a second lamp that

shows that the device is powered on Thus, a printer

may have two lights, a power-is-on indicator and a

data indicator (this second lamp often flashes) Busy

lamps are often included on modems to indicate

whether data is being transmitted or received These

lights are very useful; a user can tell at a glance if a

transmission is active

On a phone console, busy lamps are useful indicator

of which lines are currently in use, so the user can

pick up on a different line and not cut in on someone

else's conversation

busy season In any service or product distribution,

there are usually low periods and peak periods In the

airline industry, the peak periods are Thanksgiving,

Christmas, etc During these peak periods, there are

greater demands on communications systems and the

computer systems that support them Thus, software

and networks have to be designed to handle busy

times without slowdowns or loss of business

busy signal, busy tone A regularly recurring signal

(beep) on a phone line, transmitted to a caller to

in-dicate that thetrunkis not available (fast beeps) or

that the called party is on the line and cannot be

con-nected with you unless he or she has a service such

as Call Waiting If so, and the party wishes to

inter-rupt the call in progress to talk to the second caller,

he or she can do so by typing in a code, and

return-ing to the original call, if that person is still waitreturn-ing

See Call Waiting, Audible Ringing Tone

busy test In telephone networks, a diagnostic

tech-nique for determining the availability (or disability)

ofan expected service, such as a successful

transmis-sion through a newly installed line

Butler antenna, Butler matrix antenna A passive

array antenna in which the feed lines include

com-bined junctions for more than one beam Thus,

mul-tiple inputs and outputs are possible Each

beam-formed output from a Butler array can be fed to an

individual receiver Researchers have found that a

Butler matrix can be configured with smaller

num-bers of components compared to many traditional

antenna technologies Butler antennas are now used

in wireless telephony, including cell phones,

direc-tion-finding applications, and ionospheric research

systems See adaptive antenna array

butt joint A wire connection or splice in which the

ends of the conductors are butted up against one

an-other and combined by soldering, welding, etc

butt-in, butt-setSee buttinsky

butterfly capacitor Atuning device with good selec-tivity resembling a butterfly or bowtie, used for very high frequency (VHF) and ultrahigh frequency

(UHF)transmissions

butting The process oftightly aligning adjacent com-ponents, often along a planar surface For example, linear and grid arrays of fiber optic tapers are butted within fine tolerances to produce larger imaging ar-eas The tradeoff is a slight loss of image resolution

at the points where individual elements join and pos-sible increased electromagnetic interference from the large number of individual charge coupled devices (CCDs) and their accompanying circuitry There may also be overall geometric distortion, particularly in larger arrays, in which slight alignment errors accu-mulate over the extent ofthe surface Neverthless, the advantage of larger imaging areas and less edge dis-tortion than typical glass lenses makes this a good so-lution for sensors, research, and medical imaaging

buttinsky slang A type of telephone system that

in-cludes a transceiver worn on the hips that is used to

"butt in" on conversations; it permits a technician to break in on or monitor a call It is used in diagnostics and installation

button caps Portable key sleeves designed to fit over individual buttons on programmable pushbutton phones or computer keyboards These caps may be plain (for hand labeling), transparent, or preprinted,

to indicate the newly programmed or temporary func-tion of the key

buttoned up Sealed, completely closed

buzz\l. 1.colloq To catch the attention of someone

at a distance or out of eyesight To call for a quick chat on the phone 2 To press a buzzer

buzz test Diagnostic testing ofthe continuity ofa cir-cuit by placing a buzzer on one end and sending a current from the other end to see if the buzzer rings Often used when the far end is out of eyesight, but not out of hearing See buttinsky

buzzer A signaling device, usually electromechani-cal, that makes a raucous noise when the circuit is completed, at an attention-getting volume and fre-quency Buzzing noises can also be generated on computer systems Buzzers have many uses; they can catch a person's attention, indicate a fault condition,

or provide a tone that can be used as a diagnostic tool when tracing a circuit See tone generator, tone probe buzzer leads The connecting posts or wires attached

to a device that are intended for the connection of a buzzer

BVRSee beyond visual range

BW See bandwidth

BWF See EBU Broadcast Wave Format

BXcable A type of cable used in electrical wiring consisting of insulated wires enclosed within a flex-ible metal tube

BIY signal In a color television signal, BN is one of

the three primary signals (of RGB), providing blue (B) when combined with a luminance signal (Y) bypass To shunt around the normal path; to provide

an alternate path, often for temporary installation or diagnostic purposes

Lovelace, Ada Augusta.

byteA unit of data that is bigger than a bit (binary

digit) and smaller than a word The relationship of

bits to bytes and bytes to words varies according to

the system, but in most computing a byte is said to

consist ofeight bits File sizes and storage on smaller

media are usually displayed by the system in terms

of bytes or kilobytes

Many character sets encode each character within a

byte of data International character sets tend to use

two-byte encoding schemes to accommodate the

much larger number of letters and symbols In

Internet protocol documents, it is more common to

use the tenn 'octet' (8 bits) instead of the term byte,

presumably because the meaning ofoctet is more

ex-plicit See kilobyte, megabyte

BytemagazineOne of the first popular small

com-puter systems journals, founded in 1975, Byte

maga-zine is still publishing in print and on the Web while

many other computer magazines have come and

gone Robert Tinney's covers graced the publication

for a decade and a halfand Jerry Poumelle's columns

have been a mainstay for decades One of the most

popular features of Byte magazine in the 1970s and

1980s was Steve Ciarcia's circuit cellar, an

electron-ics column for hobbyists At around the same time

that Ciarcia left Byte for other activities, the tone of

the magazine changed, it became more

mM-system-oriented, and "Small Systems Journal" was removed

from the masthead

byte protocolAlist of special byte-sized binary

pat-terns used for signaling or as masks The byte

proto-col may include control instructions, delimiters,

co-ordinates, or any type of information that can be

en-coded into a byte that is relevant to a particular

ap-plication

Byte Stream File TransferBSFT.AnOpen Group

Technical Standard means for transferring

unstruc-tured files among Open Group-compliant systems

BSFT is derived from File Transfer Protocol (FTP)

but utilizes an ISO profile

byte stuffingIn its simplest sense, adding extra bytes

to a data stream Byte stuffing may be used to "pad"

data to conform to certain file fonnats such as chunky

file formats or those that must end in even-byte

boundaries Byte stuffing can also be used to mark

time to keep a link live while waiting for

continua-tion or acknowledgment Byte stuffing can be used

to represent characters that do not necessarily exist

in the transmittable data set (e.g., symbols) or to

dis-tinguish between ambiguous characters/signals

Cer-tain characters can be stuffed into the data stream to

signal a specific character at the receiving point by

mutual agreement, even if that character wasn't sent

in the actual data Byte stuffing can be used to

dis-tinguish control data (e.g., esc) from informational

data ("Hi, Alice!") Byte stuffing may signal

some-thing important or somesome-thing different to come in the

transmission scheme It can be used in error

correc-tion schemes Commonly byte stuffing is used to

en-code a signal that might be erroneously interpreted

may be sent over a network in place of an end-of-transmission (EOT) marker to distinguish it from an end-of-frame (EOF) marker

In Point-to-Point Protocol (PPP), bit or byte stuffing

~:tt~~~i :~~:::~~r:~~~~a~~et~~:~eo:~.

head to determine whether or not to admit the stuffed data stream In modem communications, the degree ofbyte stuffing can vary widely, up to almost double the original data

byte timing circuitBTC In the ITU-T X.21 Rec-ommendation, a data timing circuit in interchange circuit B For optimization, the transition to t=0 is required to occur within the same bit interval as the transition to c=ON In call control character align-ment, the Data Tenninal Equipment (DTE) may be required to align call control characters transmitted

to either SYN characters delivered to the DTE or to signals on the byte timing circuit Therear~other tim-ing circuits in X.21, includtim-ing signal element timtim-ing (S) and DTE signal element timing (X)

byte-count protocolBCP A common type of net-work protocol that utilizes a byte value in a field to designate the length ofthe payload (the message por-tion ofapacket) rather than bit patterns or special char-acters Thus, any pattern of bits can be transmitted without worrying that it might be misinterpreted

Ethernet (IEEE 802.3) is an example of a BCP

byte-stream protocolBSP Also called a stream

pro-tocol, a network protocol based upon the

transmis-sion of in-order byte-stream data, that is, bytes are written into and received out ofa connection-oriented environment at the application level (the underlying transmission may be packet-based) Transmission Control Protocol (TCP) is an example of a byte-stream protocol, as is Internet Stream Protocol,V.2 (ST2).Induplex transmission, two byte-streams are supported, one for each direction Flow-control mechanisms may be incorporated to facilitate user control See ST2+, Transmission Control Protocol

bytecodesByte-oriented machine instructions In Java programs, the platform-independent codes that execute within a Java Virtual Machine(VM).Distinct bytecodes are used by the JavaVM for operations on various data types that are on the top of the operand stack JavaVM bytecodes may also move operands between the frame and the operand stack See Java

bytes per inchBPI In recording, a measure of the amount of data that can be stored on a medium It is usually used to describe data density in media that are long and narrow, such as recording tapes See superparamagnetic

bytes per secondBps Many people abbreviate this bps, which causes confusion because bits per second

is conventionally abbreviated bps Bytes per second (Bps) is a description oftransfer or transmission rates

in bytes over time A byte is eight bits, or one octet

Data frame format sizes are sometimes described in terms of bytes or octets

Byzantine agreementA core concept instrumental

in the study and implementation of reliable,

fault-Fiber Optics Illustrated Dictionary

tolerant processing sensing systems and networks

Byzantine agreement is agreement based upon

consensus in a system processing data from multiple

sources and in which the data may not always match

Agreement may be simultaneous (simultaneous

antine agreement - SBA) or eventual (eventual

Byz-antine agreement - EBA)

The name stems from the Byzantine Generals

prob-lem proposed by Pease et al in 1980 Proofs and

veri-fications ofthe concept and fault-tolerant circuits

fol-lowed in the early 1990s, with implementations and

improvements in efficiency emerging in the

mid/late-1990s, along with authentication mechanisms for

Byzantine agreement protocols Early investigations

focused on single faults, with mixed faults (hybrid

faults) considered thereafter By the late 1990s,

al-gorithms to simulate Byzantine agreement were

be-ing released on the Internet so that the agreement

pro-cess could be observed in progress and more widely

implemented on distributed networks

Mathematicians have approached the problem in a

number ofways, since it is expedient to reach

agree-ment quickly and efficiently Bracha described

ex-pected rounds in a randomized Byzantine Generals

protocol in 1987 Halpern et al characterized EBA

in 1990 Computational Logic, Inc (CLI) verified and

implemented the original Marshall et al version of

the algorithm CLI developed a formal model

ofasyn-chronous communication based on the concept

Kesteloot suggested that executing a fault detection

algorithm before running an EBA process may save

on processing time Garay and Moses have presented

a polynomial-time protocol for coming to agreement

With regard to polynomial time algorithms, Kann has

suggested the use of a consistent broadcast protocol

for improving efficiency See Byzantine Generals

problem

Byzantine fault A type of fault that is unanticipated

or unexpected or that may result from intrusion into

a network When a network is invaded by a Trojan

Horse or other type of program, it may exhibit

tran-sient behaviors or insert seemingly innocuous code

that could be activated or triggered by various events

or states within the system (e.g., a logic bomb)

Byz-antine faults can also occur in distributed networks

where the number of nodes and the routing of

infor-mation is dynamic and not necessarily predictable

Various means of detecting, assessing, and

respond-ing to Byzantine faults are berespond-ing developed by

vari-ous organizations, especially those concerned with reliable transmissions over distributed networks, like the Internet, and those concerned about safeguard-ing computer security See Byzantine agreement, Byzantine Generals problem

Byzantine Generals problem (BGP) Aparadigm for

building consensus among distributed processes, pro-posed by Pease, Lamport, and Shostak in a SRI In-ternational Technical Report in 1980 and by Lamport, Shostak, and Pease inACM Transactions in 1982 This problem statement has revealed important con-cepts in the understanding and implementation of fault-tolerant distributed networks and multisensor imaging and data collection systems The task is to create a system that works in a reasonably correct and efficient manner in spite of faults or differences in information from multiple sources

Simply stated, there are n number of generals, with

one designated as a commander Generals can inter-communicate The task is to develop a communica-tion protocol for the commander to send an order to the generals so that all generals are obeying the same order - if the commander is loyal, every loyal gen-eral obeys the order sent by that gengen-eral Since there may be faults in the system, any of the generals could

be traitors (plotting a coup or holding erroneous in-formation) and may send information inconsistent with that of the other generals

The Byzantine Generals problem has many practical applications in telecommunications, particularly in parallel processing or distributed processing networks and in remote-sensing systems, where multiple sen-sors are providing data that may not exactly match and that must be resolved to make use of the infor-mation In other words, in these contexts, multiple inputs that may differ may need to be agreed upon before they are processed (e.g., a remote-sensing sat-ellite may have to resolve multiple inputs from sepa-rate infrared sensors or different types of sensors) The concept is useful in fault-tolerant networks for coordinating the operations of multiple independent processors The Byzantine Generals problem does not specify whether a value has to be agreed upon simul-taneously(simultaneous Byzantine agreement) or eventually(eventual Byzantine agreement).See Byz-antine agreement

BZTGerman telecommunications organization See Bundesamt fur Zulassungen in der Telekommuni-kation

or centigrade 3 symb the velocity of light.

Cminus,C- symb the negative terminal of a C

bat-tery The connecting point at which the negative

ter-minal of a grid bias voltage source is connected, as

in a vacuum tube circuit See C battery

Cplus,C+ symb the positive terminal of a C

bat-tery The connecting point at which the positive

ter-minal of a grid bias voltage source is connected, as

in a vacuum tube circuit See C battery

c++A high-level programming language, a

super-set of C, developed primarily by Bjarne Stroustrup

at Bell Laboratories.In endeavoring to be backwardly

compatible with C, it is criticized by some as being

unwieldy Nevertheless, it is widely used in

commer-cial software development and many programmers

like it See Clanguage, object-oriented programming

CbatteryAtype ofpower cell first introduced in the

early 1920s Historically, C batteries supplied bias

voltage to electron tubes that were used to control a

grid circuit C batteries are still commonly used in

small flashlights, portable radios, and many small,

portable, electronic appliances

CBlockA Federal Communications Commission

(FCC) designation for a Personal Communications

Services (PCS) license granted to a

telecom-munications company serving a Major Trading Area

(MTA) This grants permission to operate at certain

FCC-specified frequencies

The organization of radio spectra for new

technolo-gies has not been a simple process Problems arose

with the original C and F Block license allocations

assigned between December 1995 and May 1996; the

auction rules established in 1994 by the FCC did not

work well in practice Almost 1000 C and F Block

licenses were granted but, rather than creating a

com-petitive market based upon many small businesses,

the licenses ended up in the hands ofa small number

oflarge interests, some ofwhich were over-ambitious

and unsuccessful

By 1997, the FCC Wireless Telecommunications

Bureau had suspended payments on C Block licenses

but later reinstated the obligation Companies

re-sponded by declaring bankruptcy, tying up the assets

in legal proceedings As a result, the FCC cancelled

certain spectrum allocations and scheduled the

re-After further delays, the auctions finally took place between December 2000 and January 2001, gener-ating almost $17 billion in revenues Once again, the intention of the C and F Block allocations was to en-courage the development ofinnovative wireless com-munications and to increase the level of competition

in the market See ABlock for a chart offrequencies See Omnibus Budget Reconciliation Act

CinterfaceAn interface used in Cellular Digital Packet Data (CDPD) that is deployed over AMPS The C interface connects the Mobile Data Interme-diate System (MD-IS) to the IntermeInterme-diate System (IS) See A interface, B interface, Cellular Digital Packet Data, D interface, E interface, I interface

CjackThe USOC/Federal Communications Com-mission (FCC) code for a flush- or surface-mounted jack (as opposed to wall-mounted) The designation

is typically a suffix added to ll (IIC) or

RJ-45 (RJ-RJ-45C), for example See RJ for a fuller expla-nation and chart

Clanguage,'c'A sophisticated, fast, widely used, medium-high-Ievel programming language devel-oped by Dennis Ritchie at Bell Laboratories in the early 1970s 'C' was descended from B (the quotes are now usually omitted) C became widely distrib-uted with Unix and was used for programming the Amiga computer in the mid-1980s By the late 1980s, universities were teaching both C and Pascal as ba-sic skill sets, and C has become widely used in the commercial software development industry The chief advantages of C are power and flexibility Its chief disadvantages are the logistics of keeping track of pointers and memory allocation and the many pages ofcode that are needed to accomplish basic tasks The popular introductory book on C was written by Kernighan and Ritchie See C++

CleadIn communications lines utilizing three wires, where one is positive and one is negative, the third wire or C lead may be used as a ground and can be manipulated to connect or release the circuit In tele-phony, the control provided by the third wire is use-ful on trunk circuits

Clink, cross linkIn CCIS out-of-band telephone networks, a link to interconnect pairs ofSignal Trans-fer Points (STPs)

Fiber Optics Illustrated Dictionary

CNews A UUCP-based news-reading program

de-veloped from the earlier A News and B News

pro-grams Along with InterNetNews (INN), CNews

su-perseded B News The networks were changing,

TCP/IP had been introduced along with Network

News Transfer Protocol(NNTP).CNews, written by

Geoff Collyer and Henry Spencer of the University

of Toronto, was released in fall 1987 C News was

faster, more reliable, and supported a bigger article

database than previous versions A port of C News

for AmigaOS was developed by Frank Edwards See

ANews, B News, USENET

CSeries Recommendations A series ofITU-T

rec-ommendations that provides guidelines for general

telecommunications statistics These guidelines are

available as publications from the ITU-T for purchase

and some may be downloaded without charge from

the Net Note that the statistical yearbook was

trans-ferred to ITU-D Since ITU-Tspecifications and

rec-ommendations are widely followed by vendors in the

telecommunications industry, those wanting to

maxi-mize interoperability with other systems need to be

aware ofthe information disseminated by the ITU-T

Afull list ofgeneral categories is provided in

Appen-dix C and specific series topics are listed under

indi-vidual entries in this dictionary, e.g., A Series

Rec-ommendations

ITU-T C Series Recommendations

C.1 1993 lTU statistical yearbook (deleted,

activity transferred to lTD-D)

C.2 1996 Collection and dissemination of official

service information

C.3 1993 Instructions for international

telecom-munication services

C-band A portion of the electromagnetic spectrum

used extensively for the transmission of radio wave

communications signals, especially those to and from

satellites The C-band extends from 4 to 8 GHz with

satellite uplinks in the 5.925- to 6.425-GHz range,

and downlinks in the 3.7- to 4.2-GHz range

Down-link and upDown-link frequencies are different in order to

reduce interference between received and sent

sig-nals C-band transmissions require relatively large

re-ceiving antennas, making them less popular for

con-sumer services than Ku-band See band allocations

for chart See C-band, optical

C-band, opticalInoptical communications, an

lTU-specified transmission band in the 1530 to 1565-nm

range that is used for fiber optic transmissions and

which recently is sometimes supplemented with

L-band transmissions over the same cable (in

multi-mode cables) See C-band

C-Scope In radar, a screen that displays bearing and

elevation information relative to the center of the

re-gion being scanned

C-plane InATM networking, as it applies to a

Broad-band-ISDN reference model, the C-plane is the

con-trol plane, a higher-level plane including all of the

ATM layers, which bears control signaling informa-tion It sits adjacent to the U-plane (user plane) and shares physical andATM layers with the U-plane The M-plane (management plane) enables the transfer of information between the C- and U-planes In ATM networking, as it applies to Frame Relay bearer ser-vices, the U-plane parameters, such as throughput, maximum frame size, etc., are negotiated through the C-plane See the Appendix for more detailed infor-mation on ATM

C-stock Bell Telephone jargon for refurbished tele-phone equipment

CIA Code, civilian code, S-codeInthe Global Posi-tioning System (GPS), a Clear/Acquisition Code in which the carrier wave is modulated with a sequence ofpseudo-random, binary, biphase signals to provide civilian locational information transmissions This in-formation is at a lower resolution level than the clas-sified government GPS transmissions

CIDTAC See Consumer/Disability Telecommunica-tions Advisory Committee

C64 See Commodore 64

C7 The European analog to the North American Sig-naling System 7 (SS7), which is similar but not di-rectly compatible C7 is widely deployed for digital phone communications See Signaling System 7

CA See call appearance

CAB See Canadian Association of Broadcasters Cabeo, Niccolo (1586-1650)AnItalian scholar and experimenter who recorded a number ofelectrical ob-servations and wrote the first Italian treatise on

mag-netism, Phi/osophia magnetica, in 1629.

cable Wire, fiber, or other conductive material in single or multiple (bundled) strands used for the trans-mission of light, heat, electricity, or data Although

the terms wire and cable are often used

interchange-ably, some technicians make a distinction based upon the bundling If it is a single metal core, it's called a wire, if it is a combination of layers of two or more separately insulated wires, or if it is a fiber optic

bundle, it's called a cable A fiber optic cable may

support a single fiber or may support a bundle rang-ing from 2 to over 400 fibers

In telecommunications, the speed and quantity ofdata that can be conducted along a cable varies greatly with the materials that are used in its manufacture Traditional phone lines are usually copper wires, while cable television broadcasting uses fiber optic cable with greater speed and bandwidth The com-puter industry, with its demands for simultaneous transmission of data, sound, and video, has greatly increased interest in high-speed, high-bandwidth cable media Wireless services such as cellular phone and individual satellite modem transceivers provide

an option to physical cable links See conductor, con-duit, creel, fiber optic, swelling tape

cable, armored A cable reinforced or wrapped in a strong, environment-resistant or vandalism-resistant covering, usually of wound metal Armored cables are sometimes used to chain costly equipment, like computer terminals, to walls or work desks, to pre-vent theft Armored cables are sometimes used on

and penal institutions (to prevent the handset or the

cord itself from being cut away and stolen)

External fiber optic cables may have an extra layer

of annoring to prevent damage from lightning or to

discourage rodents from chewing through the cable

See annoring, ballistic

Examples of Basic Fiber Optic Cables

_2_ _.11_2_ _ _ _ _ ? _ _ J _ _

-simplex

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duplex - combined housing

duplex - joined housing

duplex - armored, combined housing

The top three cables are examples of basic,

low-fiber-count, indoor fiber optic cables The bottom is

an internal/external armoredfiber optic cable that is

resistant to rodent and lightning damage.

cable, interconnectA cable intended for local

con-nections such as fiber to the desk (FTTD), patch

cables between systems, and point-to-point runs

through buildings Interconnect cables tend to be

flex-ible, with a small diameter and bend radius, with

ad-equate to good shielding Interconnect cables may be

single-mode or multimode and are usually

compat-ible with standardized connectors

Cable & Wireless (Marine) Ltd.The world's

lead-ing supplier ofsubmarine telecommunications cable

equipment and services in the 1990s, Cable&

Wire-less was restructured as part of Global Marine Ltd

cable access, PEG By regulation, cable television

broadcast providers must set aside and reserve

chan-nels for use by the public, educational institutions,

and government entities (PEG) The cable company

is limited from exercising editorial or content

con-trol over these public and government programming

channels

Cable Actof1984An Act of the u.s. Congress

broadly deregulating the cable TV (CATV) industry

This significantly reduced the Federal

Communica-tions Commission's (FCC's) jurisdiction in this area

In 1992, the Act was partially repealed and further

shaped by the Cable Reregulation Act of 1992

Cable Act of 1992 Presented as the Cable

Reregulation Act of 1992, it is now commonly called

the Cable Act of 1992 This Act arose from the Cable

Act of 1984 to provide a regulatory framework for

steadily increasing cable services Cable television

these regulations and the Act has recently been scru-tinized for its relevance to interactive television ser-vices See Telecommunications Act of 1996, basic cable service

cable assemblyApre-assembled cable, ready for in-stallation (e.g., fitted with jacks or other relevant at-tachments)

Armored Cable Assembly

a

b

c

d

e ~M,

f - mil

~=I

Armored cables have extra reinforcing in the cable housing to prevent damage In this basic armoredfi-ber optic bundle, the outer sleeve (a) provides protec-tion against wind, solvents (e.g., water), and abra-sion It is often made ofplastic (e.g., polyethylene) The next layer (b), between the sleeve and the inner jacket, is an armoring layer ofmaterials that are dif-ficult to cut, chew, or burn, such as steel tape The armoring material also helps prevent the fiber from being inadvertantly stretched during installation Ripcords (c) may be provided directly under the armoring and the inner sleeve to aid in stripping the layerfor splicing the cable to connectors or termina-tors The inner sleeve (d) is a protective, oftenflame-retardant, layer to support the inner cable bundle The inner bundle (e) includes torsion members, fillers, or other structures to support the numeric- or color-coded cladding layer (f) that keeps the lightwave within the fiber filaments (g) A central member (h) ofsolid or stranded plastic-coated steel, for example, may be included as a supporting strocture Gel-jilled buffer tubes may surround individualfibers (not shown here).

cable bayAninstallation setup designed to accom-modate many sets of cables in rows or a matrix, to facilitate easy access, identification, and mainte-nance

cable connectorAnassembly for facilitating the cou-pling of cables to systems and components and to other connectors (e.g., adapters) Cable connectors come in many configurations and sizes in a variety ofmaterials including plastic, ceramic, stainless steel, aluminum, resin, or rubber Due to their flexibility

in fabrication and relatively good water resistance, plastic connectors are common Where electrical

Fiber Optics Illustrated Dictionary

shielding is desired, metal may be used A cable

assembly is a cable with connectors already installed.

In fiber optics, where preservation of the light beam

is crucial to correct functioning, it is important to use

well-designed and fabricated cable connectors

Splic-ing the fiber for attachment to a cable connector is

also critical and special tools have been designed for

this purpose In multimode fibers, individual fibers

may be color-coded or numbered to facilitate

connec-tions

Labeling conventions are used in the fiber optics

in-dustry to identify certain configurations and coupling

mechanisms (see Fiber Optics Connector Types

chart) The abbreviations describing a cable

connec-tor are typically followed by a size Thus, SCIAPC

SM(3mm) would describe a standard connector with

an angled physical contact supporting 3 mm

single-mode fiber connections

Good connections are critical to preserving the

per-formance of fiber optic components As new fiber

optic connectors are developed, they may not couple

directly with existing fiber optic instruments

Adapt-ers may be available from the device manufacturer,

for coupling with new cables It is important to use

adapters that preserve calibration accuracy ifthey are

coupled to precision instruments

cable core The inner, conductive portion of a

sheathed or insulated cable The fiber waveguide in

a fiber optic cable

cable coupler A hardware connector used to

com-plete the circuit between similar or dissimilar cables

with the same electrical or optical transmission

char-acteristics Depending upon the context, cable

cou-plers may also be called splice bushings or mating

adapters A mating adapter enables the coupling of

two cables with different connectors See cable

con-nector

Cable Deregulation Act of 1992 In 1984, an Act of

the u.S Congress that broadly deregulated the cable

TV (CATV) industry The Act significantly reduced

the Federal Communications Commission's (FCC's) jurisdiction in this area In 1992, the Act was partially repealed and further shaped by the Cable Reregulation Act of 1992; rates were mandated to be lowered by an FCC-prescribed percentage in 1993 and again in 1994 It is now more commonly called the Cable Act of 1992 See Cable Act of 1992 cable diameterAnimportant indicator ofthe size and other properties ofa cable The diameter ofa wire or fiber optic cable can dramatically affect its transmis-sion properties, weight, flexibility, cost, and ease with which it can be interconnected with other compo-nents It may also influence the distance over which

it can carry a signal See American Wire Gauge, Birmington Wire Gauge, fiber optic, multimode op-tical fiber, single-mode opop-tical fiber

cable drop The subscriber connection segment of a

wired cable access installation The cable drop is generally the section that originates at the cable tap

on a utilities pole and ends at the subscriber's televi-sion or at a connector fed through the subscriber's wall to which the subscriber can hook the television Cable/lnformation Technology Convergence Forum CITCF.Anorganization representing the cable indus-try that was established to further communication be-tween vendors and cable industry professionals cable lossAnimportant property of a cable's trans-mission characteristics over distance Loss ofsignal,

or attenuation, is the gradual diminution of the

sig-nal to the point that it is no longer useful or can no longer be detected at the receiving end Loss may be due to many factors that often occur together, includ-ing interference, the construction and materials used

in the cable, the number ofconnections, the proxim-ity of other conducting surfaces, the thickness, dis-tance, weather conditions, etc

Some types of transmissions can be carried over only

a short distance For example, external SCSI device cables are usually limited to lengths of about six feet and shorter cables are recommended With Fibre Fiber Optics Connectors

ST straight tip, standard termination A metal or plastic housing with a bayonet connecting

mount;aferrulecylinder supports and aligns the fiber

SC standard/subscriber connector Aninexpensive, plastic, molded connector commonly

used in residential applications, designedby NTT; SCto

SC and SC to ST duplex patch cables are common

LC - A newer, small-format coupler that takes up only about

half the space of SC connectors when mounted in racks The following abbreviations may follow the above connector types as suffixes (e.g., ST-PC):

PC physical contact Promotes fiber to fiber contact in the coupling

AC angled contact Fiber end is polished at a slight angle, thus reducing

movement at the coupled joint APC angled physical contact

SM single mode

MM multimode

can be extended enough to use a separate maintenance

room for aggregating the devices For many types of

optical fiber installation, the transmission distance

may be only a couple ofkilometers See attenuation,

multimode optical fiber, single-mode optical fiber

cable mapA diagrammatic record of the type and

location ofcables in a distribution system For decades,

hand-drawn cable diagrams were used More recently,

computer-generated diagrams and databases are

sometimes used to keep track To aid with local

man-agement, cables are frequently color-coded, marked,

or bundled, and this information mayor may not be

redundantly recorded on the cable map

Cable maps are particularly important in institutions

and business complexes serving many rooms and

buildings, and in submarines and ships that have

sub-stantial numbers ofcables running through corridors

and walls.Indata networks, the physical cables

be-tween routers, switchers, and workstations are

some-times diagramed in the routing software, displayed

as a color-coded schematic on-screen These

appli-cations may have two types ofmaps included in them

- a physical cable map, and a virtual connection map

- one ofwhich is laid over the other and each ofwhich

may be managed somewhat differently

cable modemThis phrase is used to describe both a

device and a network service option that together

enable computer access to high-speed transmissions

via a broadcast cable network and subscriber service

Cable modem services are delivered through copper

or fiber optic cables to the local drop (usually atap

on a utility pole oustide the premises) that leads to a

connecting panel on the building From there, the

cable is connected to a specialized modem on the

sub-scriber premises through a coaxial cable

In many areas, the service is virtually 'live' all the

time, although some ISPs will time out and

recon-nect specific Internet conrecon-nections if the line is 'idle'

for long stretches of time Since the majority

ofcon-sumer subscribers are assigned dynamic IP numbers,

the ISP will time out the idle subscriber and assign

the dynamic IP to another user, thus more efficiently

utilizing resources When the subscriber attempts to

reaccess the service, a new IP number is assigned or,

if the "lease" on the existing IP number is still

avail-able, the same number will be reassigned Some cable

modem users may have static IP numbers or may be

using cable modem services to create a virtual local

area network, in which case timeouts may not be used

Although many digital data service cables can handle

two-way communications, most implementations

tend to be asymmetric, giving more time to the

down-stream data (since most information is downloaded

from source to user) Cable can deliver broadband,

round-the-clock, fast access to data services such as

the World Wide Web, without tying up phone lines

Cable modems enable users to download information

about 20 times faster than ISDN modems, and about

80 times faster than 28.8K phone line modems 360K

cable modems began shipping in 1997; by 2000, the

service was widespread in urban centers The price

Asymmetric Digital Subscriber line, ISDN

cable plowA specialized plow designed to dig trenches specifically for the installation of under-ground cables on land or underwater Modem under- ground-based systems can install numerous cables or cable

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ting are called open-cut plows, those that disturb the earth with vibrations are vibratory plows Each has advantages but, in general, vibratory plow trenches are generailly easier to cover over again

cable riserVertical support for cables that are in-stalled in walls and ceilings, in order to reach upper floors in multiple-story buildings

cable runA conduit or other piping or pathing sys-tem that provides a means to thread cables or that constitutes the path ofthe cables Cable conduit runs are used for a number ofreasons In some cases, they make it possible to add cable later, if the full cabling requirements are not known at the time the run is in-stalled They may provide extra insulation or fire pro-tection, and they may be more aesthetic, enclosing a bundle of cables that might otherwise be distracting

or unsightly

cable tapIncable accessinstallations, the tap is the physical connection, usually on a utilities pole, to which the subscriber line is attached

cable television, community antenna system CATV A television broadcast system that transmits licensed television programs and local programs to subscribers over a wired network, usually over fiber optic cable Cable~that is, television broadcast de-livered over wire, was established in Europe in the early 1930s, less than a decade after the viability of the television medium was first demonstrated In North America, the distances between communities was much further, and cable TV was slower to de-velop Satellite transmission options to cable televi-sion are becoming more widely available See basic cable service

Cable Television Relay Service StationCARS A television relay station is a transceiving point between the original broadcaster and the subscriber It may be

a building facility, an unstaffed tower relay, a mobile relay, or other point at which the transmission is re-ceived, sometimes processed, and then retransmitted For example, the broadcast may be sent over aitwaves

to the local relay station, which may be a local cable

TV supplier Once the various broadcasts are re-ceived, the local station subsequently sends the sig-nals to the subscribers through physical cables This way there is only one powerful antenna needed to serve the local area (otherwise each subscriber would need an antenna, the way it was before cable TV be-came available) It also gives the local station the ca-pability oftransmitting only those stations that the sub-scriber may desire or that fit the payment package ar-ranged with the local station

cable vaultAnenclosed area, often in a basement with extra fire-proofing, that encloses a large number