This informa-tion was originally recorded manually, and operators of public phone systems had elaborate card systems on which to record calls, particularly long-distance calls.. A teleph
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ofcables leading into a building or distribution frame
Cable vaults are usually used in situations where the
type or number of cables pose extra fire or
electro-cution risks, and where it is desirable to restrict
ac-cess to qualified personnel only
cablehead The point at which a land cable and
ma-rine cable are joined It may be indicated with a sign
(as are seen on ocean beaches)
cableway A hole, slot, or other opening in a
compo-nent unit or work surface that allows cables to be fed
into the fixture from behind or beneath Most
com-puter desks now include slots and holes for cables
Some even put slots into the drawers, so a printer can
be installed in a drawer and pulled out as needed
Cabling Standards UpdateA quarterly newsletter
describing high-speed network trends, technologies,
standards activities, and economic indicators for a
range of transmission media, including copper wire,
glass and plastic optical fiber, coaxial cable, and
wire-less, published by Information Gatekeepers, Inc
CAC I Customer Administration Center A phone
console used for maintenance and diagnosis of a
multiline phone system 2 See call admission
con-trol, connection admission control
cachev.In the traditional sense, to cache something
is to put it away or hide it in a secure place for later
use In computer terminology, the sense of putting it
away for later retrieval is retained, but ease ofaccess
is also implied Thus, to cache is to store
informa-tion in an accessible locainforma-tion, as in RAM on a
com-puter, so it can be retrieved quickly when needed
Many systems are specifically configured with cache
memory, while others may use the hard drive as a
cache location, which is not as fast but still may be
effective in certain circumstances Information is
cached by an applications program for items that are
often consulted or executed This speeds up
opera-tions for priority activities See cache, cache memory,
RAM disk
cache, cache memory A high-speed electronic
memory buffer used in computing to increase
appar-ent processing speed by more effectively managing
resources The cache storage is usually within a
des-ignated amount of random access memory (RAM)
and thus is volatile, (although in its most generic
sense, a hard drive would be a suitable cache device
for a slow sequential storage medium like a tape
drive) Ahard drive controller card may itself include
a cache
The effectiveness of a cache depends upon a variety
offactors, including the size of the cache, the ability
of the software to utilize it, the types and variability
of operations being done, the design of the caching
logic, and the speed of the microprocessor Since
RAM access is typically faster than hard drive access,
efficiency can be increased by storing frequently
ac-cessed information in the cache memory, where it can
be written and retrieved more quickly than from disk
Information that is not found in the cache may then
be added to the cache for future reference In
network-ing, a cache can be used to store frequently accessed
information (often the locations or contents of data
files or applications) in order to serve it more quickly
to users, as it is requested FATs and hash tables may
be stored in the cache to increase file access speed BIOS device-controlling functions may be loaded from read only memory (ROM) into cache memory during a startup sequence See cache, cache hit, cache miss
cache controller In some computer architectures, a circuit that is specifically included to administer the storage, organization, and retrieval of cached infor-mation This may be incorporated into a specialized chip
cache hitAsituation in which the data that was sought
in a cache access was found and it is not necessary to access the slower storage medium (usually a hard drive), resulting in faster retrieval of the desired in-formation See cache, cache miss
cache miss A situation in which the data that was sought in a cache access was not found and is conse-quently sought on the slower storage medium (usu-ally a hard drive) It may subsequently be stored in the cache for future reference See cache, cache hit caching Putting information in a storage area where
it can quickly be retrieved when needed It is a means
of speeding up effective and perceived performance
of a system Disk caching and memory caching are two ways to speed up access to frequently used com-mands, device drivers, or frequently accessed data caching, data entry A means of speeding up data entry by retaining previously inserted information so that it can be reused or overwritten for subsequent entries It's often more efficient to edit or retain the data in the field from the previous entry than to type
it in from scratch
CACM I California Association of Community Managers, Inc 2.Communications ofthe Association for Computing Machine/Yo The communications
jour-nal of the ACM, one of the many ACM professiojour-nal publications
CAD 1 See computer-aided dispatch 2 See com-puter-aided design/drafting
cadence A rhythmic measure or beat In telecommu-nications, many signals are identifiable by a pattern
of tones and silences Cadence has implications for telegraph, radio, and telephone communications where many audio signals are coded to particular rhythms (Morse Code, distinctive ringing, interna-tional variations in rings, and busy signals) People can learn to distinguish different types of data com-munications by pitch and cadence, as fax tones dif-fer from data tones, and data tones vary further ac-cording to baud rate
cadmium A bluish-white, malleable, ductile, metal-lic, noncorrosive element that is commonly used in protective coatings and platings
CADS I code abuse/anomaly detection system
2 computer abuse/anomaly detection system Sys-tems put in place to detect, log, and/or signal prob-lems that may be due to tampering or other unautho-rized use
CAE I See Common Applications Environment
2 computer-aided engineering
Trang 2cage antennaA multiwire antenna (imagine a ring
of horizontal parallel wires somewhat constricted in
the middle, resembling a cage) similar to a dipole
antenna, configured to improve capacity and reduce
loss
CAl 1 See computer assisted instruction 2 common
air interface An international interface standard defined
to provide interoperability between wireless handsets
and compatible networks
CAL 1 CAN Application Layer See CAN in
Auto-mation, Controller Area Network 2 computer-aided
learning, assisted learning See
computer-assisted instruction
CALC See customer access line charge
calculatorA device for facilitating fast, accurate
mathematical computations Early calculators
(add-ing machines) could handle only simple arithmetic
functions, while current ones include storage,
auto-mation, and programming capabilities for doing
fre-quent or complex computations
The calculator is the forerunner of the general
pur-pose computer; in fact, the early computers were very
large, very powerful calculators, and their histories
run hand-in-hand Then, as computer technology
im-proved, memory and logic functions were scaled
down and incorporated back into calculators
In 1940, Remington Rand Inc was advertising a
"printing calculator" that was essentially a
mechani-cal adding machine that used impact printing like a
typewriter to record the tallies Until the late 1960s,
"advanced" calculators were too expensive for
indi-viduals and small businesses By 1969, however, the
Friden Division ofSinger was advertising a
desktop-sized version of an "electronic calculator that can
remember up to 30 mathematical steps for you."
Handheld calculators devised in the late 1960s
be-came widespread in the early 1970s, costing about
$200 for a very simple palm-sized arithmetical
cal-culator As prices came down, calculators superseded
slide rules and abacuses for quick computations
Ad-vanced calculators for under $15 are now
common-place
The most celebrated early microcomputer was
devel-oped in 1974 by MITS, a company that was
produc-ing scientific calculators With competition from
big-ger companies such as Texas Instruments, MITS
needed a new source of revenue and developed the
Altair Since that time, calculators have been
incor-porated into many devices, such as cash registers and
wrist watches, and even some computer keyboards
Current calculators include graphical displays, square
root computations, multiple memory registers, and
programming languages such as Forth They are more
powerful than computers from the early 19802 See
abacus
calendar routingAn administrative method for
di-recting inquiries according to the time ofyear, week,
or day Used especially in industries where inquiries
are cyclic (travel industry), or where availability of
personnel to assist callers is cyclic
calibrate1 To set, align, or mark a measuring or
tim-2 To ascertain, record, or correct variations in a mea-suring or timing instrument with reference to another,
or to an accepted standard
California Education and Research Federation NetworkCERFnet This research and education net-work was founded in the late 1980s by General Atom-ics, with aid from a National Science Foundation grant, and grew to be a national backbone by the early 1990s CERFnet joined with other nets in 1991 to form the Commercial Internet Exchange (CIX) In
1996, the Teleport Communications Group Inc (TCG), one ofthe largest competitive local telephone companies in the U.S., acquired CERFnet to provide Internet services to corporate and institutional clients CERFnet is based onATM and SONET architectures, with each Local Access and Transport Area (LATA) served by at least two backbone nodes
call1.lJ.i.To attempt to contact or to succeed in con-tacting another party or entity A unit o( virtual or human communication across some type
ofcommu-nications medium or at some distance 2 n A unit
comprising a successful communication through some type of communications medium, or at some distance, between two or more parties or entities who are more or less simultaneously in contact, frequently with a 'give-and-take' character to the contact Hu-man participants in a call are generally called par-ties to the call 3 n In networking, a communications
association between a user and a network entity or between two or more users across the network
call abandons, abandoned callsCalls that are ter-minated by the originator before completion of the intended contact For telephone calls, reasons for abandoning calls includefuzzyconnections, wrong numbers, answering machines, being put on hold, ob-noxious hold music (not all hold music is obob-noxious, just some ofit), even more obnoxious hold commer-cials, interruptions (children, doorbells), transfer to the incorrect person or department, etc
Since any call connection in progress has impact on system capacity, abandoned calls have to be consid-ered when structuring and managing a system In commerce, if a high proportion of abandoned calls occur after a human operator has made verbal con-tact with the caller, it's important to determine and evaluate the reasons and take corrective measures to increase call completion See abandoned call cost
call accepted signalIntelecommunications, a call control signal sent by the receiving data terminal equipment (DTE) to indicate acceptance of the in-coming call
caU accounting systemA system of recording the type and quantity ofcalls on a system This informa-tion was originally recorded manually, and operators
of public phone systems had elaborate card systems
on which to record calls, particularly long-distance calls Now accounting has been computerized, and the system can constantly monitor call volume, num-ber of connects, numnum-ber of abandons, peak hours, trunk allocation, and other statistics related to eco-nomics in general and call billing in particular When
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used in private branch systems, it can further be used
to track agent activities, length of calls,
departmen-tal use, etc and integrated with revenue and customer
databases to give an overall picture of the role of the
phone callswithin the company's business See call card
call admission control, connection admission
con-trol CAe The set ofactions taken by a network during
a call setup or renegotiation to evaluate whether to
accept or reject a connection or re-allocation request,
based partly on the ability to supply Quality of
Ser-vice (QoS) See crankback
call announcement A feature in a telephone system
in which an operator or other agent announces the call
to the callee before connecting the call
call appearance CA I A telephony designation for
equipment that provides easy handling of volume
calls on a central console Call appearance refers to
the ability to see the calls that come in, usually
through LCD indicators and/or LED displays for the
various extensions, in order to manage and direct the
calls and monitor which lines are in use 2 A
gen-eral reference to the format in which call
informa-tion is displayed on a monitor or CED telephony
dis-play In some systems, the user can custom
config-ure Callerilland other information
call attempt Initiating a call that mayor may not be
completed If a large number of call attempts are not
completed, diagnostic and troubleshooting steps
should be taken Solutions may include training,
ad-ditional lines, staff changes, or equipment changes
or repairs See call abandons, abandoned call cost
call barring Prevention or elimination of all calls,
or specific calls, associated with a specific phone
Usually implemented to prevent unauthorized use, or
abuse See call blocking
Call Before Digging A safety sign to warn area
work-ers that they must call for information on underground
cables or hazards before digging
call block A restriction put on a phone line to
pre-vent connection of certain calls More recently it has
come to mean retaining anonymity from Callerill
by blocking the caller's identity from the receiver if
the caller has keyed in a blocking code Call
block-ing in this sense is free, whereas Caller lD costs
money This situation may seem backwards, like
al-lowing a stranger through the door unseen, while the
person opening the door has to pay money to see who
it is and still may not get the information because that
person is disguised (blocked) Interms of personal
safety and security, it should have been set up the
other way around, with the person answering the
phone being provided the identity of the caller for
free, and the caller having.to pay to hide his or her
identity However, the system was probably set up
with Callerillas a subscription service because it
generates more revenue for the phone company
call card Amanual call management and billing
sys-tem in which the information about the caller, callee,
distance, and duration of the call is recorded by the
operator See call accounting system
call center A centralized telephone call facility
han-dling a large number of calls Call centers may be
specialized for handling many incoming calls, such
as those resulting from television marketing through toll free numbers, or many outgoing calls, as those originating from telemarketing or teleresearch firms
Inthese specialized environments, automatic call dis-tributors, head sets, computerized dialing, and auto-mated answering are commonly used
call clearing The process by which a call connection
is released and the call resources made available to other users It is particularly important in end-to-end transmissions in which the line must be freed before
it can be used again
caU control The entire process of detecting a call
re-quest, setting up the physical and logical connections, rerouting to available trunks if necessary, facilitating transmission, shutting down the call, and freeing the resources for other callers Most of these functions are now computerized, although occasional operator assistance, directory assistance, or services for spe-cial needs users are still handled by human operators Call control may go through more than one system,
as when a call goes into or out of a private branch exchange (PBX) and through a public exchange, or where wireless and wireline services from different providers are used together to complete a call
caU control signal Any signal used in automatic
con-nection and switching systems that controls the call sequence In older systems, the control signals were transmitted by means of tones on the same line that was used for the voice transmissions In newer Sig-naling System 7 (SS7) systems, the control signals and the voice transmissions are handled over sepa-rate channels See Signaling System 7
call data The statistical information associated with
a call This is used for monitoring, accounting, man-agement, and planning, and these days is usually stored in a computer database, and sometimes orga-nized and analyzed by computer software
Call Detail Record CDR A telephone
record-keep-ing system, usually used for accountrecord-keep-ing and admin-istrative purposes, that tracks and records details about incoming and outgoing calls such as the call duration, caller and/or callee, time of day, etc
call diverter A subscriber surcharge service or phone
peripheral device that intercepts an incoming call and forwards it to a phone operator or phone message, or
to another number, as in Call Forwarding Depend-ing upon the service or device, the caller mayor may not be aware that the call has been diverted
call duration The period of time from actual
con-nection of the call, until its termination On phone lines and data networks, call duration information is used for statistical purposes for tuning the system, determining peak hours, and billing It may also be used to detect and diagnose fault conditions
call establishment The process of routing and
con-necting a phone call or data transmission path
Call for Votes CFY A formal process used as part of
the sequence ofevents necessary to create a new pub-lic newsgroup on USENET
Call Forward A surcharge or bundled phone service
that permits the subscriber to automatically redirect
Trang 4cases where the callee is temporarily at another
lo-cation, or where the callee wishes someone else to
handle calls (such as an answering service) On
con-sumer systems, the call forwarding is usually enabled
by using a touchtone phone to dial a code (72# on a
touchtone phone or 11 72 on a rotary phone in N.A.)
followed by the number to which the calls are being
forwarded It is disabled by dialing a code (73# or
1173 inN.A.).Some newer phone systems have an
indicator light to show that the calls are being
for-warded to prevent the subscriber from forgetting to
deactivate Call Forward after returning to the
origi-nallocation See Call Forward Busy, Call Forward
No Answer
Call Forward BusySimilar to Call Forward, except
that calls are rerouted to a predetennined number only
if the called number is busy; otherwise it rings
through to the original number See Call Forward
Call Forward No AnswerSimilar to Call Forward
Busy, except that calls are rerouted to a predetermined
number only if not answered after a specified
num-ber of rings See Call Forward Busy, Call Forward
Call Forward Variable Acombination of Call
For-ward Busy and Call ForFor-ward No Answer in which
the call is rerouted to a predetermined number if a
busy signal is encountered, or if there is no answer
after a specified number of rings See Call Forward
No Answer, Call Forward Busy, Call Forward
Call GirlsOne of the many colloquial names given
to the early female telephone operators Others
in-cludeHello Girls, Central, and Voice with the Smile.
See telephone history
call handofTInmobile phone systems based upon
passing the transmission on to another transceiver
while the call is taking place, as in cellular
commu-nications, the handoff is the point at which the call is
transferred during the conversation Mobile
provid-ers strive to create systems where the handoffis
seam-less and does not create delays, noise, or significant
volume changes
Call Hold Asurcharge phone service or multiline
subscriber feature in which the subscriber can put a
call on hold, accept or place a second call, and then
return to the original call This service is similar to a
hold button on a multiline phone, and the person on
hold is not able to hear the second conversation
call horn alert Amobile system set to beep a car hom
to signal an incoming call, when the driver is away
from the mobile handset or receiver
callmix Telephone calls are of many kinds, as are
logons on a computer.Ina telephone system, the calls
may be long or short; busy, abandoned, or completed;
local or long-distance On a computer system, the
logons may result in downloads, modem access,
run-ning of applications, file maintenance, etc The call
mix is a statistical look at the types ofusage that
oc-cur on a network
call not accepted signal In telecommunications, a
call control signal sent by the receiving data
termi-nal equipment (DTE) to indicate rejection of the
in-coming call
allows a user to set the call so it can be answered on any other phone on the system Call Park is useful in situations where the callees are moving around, and where they may be alerted to the presence of the call through a paging system The parked call can then
subscriber feature that permits a subscriber to inter-cept a call to another prearranged number by typing
in a code and then answering the other call Suppose you and your housemate have separate lines, and your housemate has asked you to answer his or her calls;
you can do so from your own phone See Call Pickup Group
Call Pickup GroupCPUG All the phones in a sys-tem through which Call Pickup is activated and that can intercept the calls ofthe others See Call Pickup
call processingA combination of computer and hu-man operations in which the call is often set up and connected electronically and then handed off to a credit collector, researcher, telemarketer, technical supporter, or other agent, once the connection has been established See call center
call progress signalAtelephone switching signal that indicates whether the call is generating a busy tone,
a ringback tone, or an error See ringback
Call RecordA data record of call details, which in-cludes information such as date and time, call dura-tion, call routing, stations used, time on hold, etc This information may be used for billing and administra-tion
Call RejectionA subscriber surcharge or bundled telephone service that enables the callee to reject an unwanted call There are two ways to put Call Re-jection into effect The subscriber can dial *60 (in N.A.), and follow instructions for entering an origi-nating number to be rejected, or can activate Call Rejection immediately after hanging up from a call that is unwanted in the future Call Rejection can be deactivated by dialing *80 (in N.A.)
call release timeThe duration during which a call is shut down and the line released for the next call
call reoriginationAhandy feature in which calls can
be initiated one time during a multicall session with
a debit card, charge card, credit card, or calling card account In other words, a series ofcalls can be made
at the same time without having to re-enter codes or having to re-insert the card to make the subsequent calls Between calls, a code is usually pressed, and the caller receives a signal to continue with the next call This feature is particularly useful when having
to make several calls at an airport to let peopIe know your flight plans have been changed and you are catching a plane at a different departure gate
call restrictor Aphysical or virtual call blocking mechanism that controls the type of outgoing calls that can be made on a line Examples include block-ing long distance calls from a phone near a public area, or blocking 900 calls from phones used by teen-agers
Trang 5Fiber Optics Illustrated Dictionary
Call Return A subscriber surcharge option that
allows the last caller, whether the call was answered
or not, to be dialed back automatically It can be handy
for crisis centers and other emergency services
call routing tree A diagrammatic representation of
call routing configuration and logic See call tree
call screening The most familiar call screening is a
receptionist who says the boss is in a meeting and
can't be reached at the moment when the boss is
ac-tually watching the World Series with his or her feet
up on the desk More legitimate uses of call
screen-ing involve gettscreen-ing enough information from the
caller to direct the call to the best person equipped to
handle it In automated systems, call screening is a
setup that uses Cal1er ill, or some other
identifica-tion tool, to monitor the origin ofthe call and to patch
it through accordingly, or that uses a speech
recogni-tion system to direct the call
call sequencer An automated system for evaluating
incoming calls, queuing them if necessary, and
as-signing them to agents depending upon priority,
avail-ability, or cal1er characteristics
call setup timeIna circuit-switched network, such
as most phone networks, the amount oftime it takes
to patch through the route from the caller to the
des-tination in order to set up an end-to-end path for the
communications During the course of a call, the
re-sources are dedicated to that communication and
can-not be used by others For a phone cal1, the call setup
time includes the time it takes to dial and for the cal1
to be switched through the system and the
appropri-ate trunks to the destination This time is usually not
billed for land lines (wireless may be bil1ed for air
time) since it is not known during setup whether the
call will be answered and how long it will last
call shedding A situation in which automatic cal1
handling systems are used to drop (shed) a phone
con-nection if no sales agent is available to talk to the
callee when he or she picks up the line If all agents
are busy when a cal1ee answers an automatically
di-aled cal1, the cal1ee may hear a recorded message and
be put on hold More commonly, however, the call is
shed; the callee hears a click and a dial tone and has
no opportunity to speak to a human agent This
prac-tice is very annoying and illegal in many areas
call sign See callsign.
call splitting A subscriber surcharge or private branch
service in which a conference call participant can
speak to anyone of the other members of the
confer-ence privately, that is in nonconferconfer-ence mode When
a phone attendant is involved in the call, the
atten-dant may relay the information privately to one ofthe
called parties
Call Stalker An AT&T commercial software
pack-age providing 911 emergency service pack-agents with
in-formation about the caller, such as address and
call-ing phone number
call supervision A process for determining whether
a telephone communication was actually answered,
so billing is not activated unless a connection was made
Call Trace A surcharge phone service or emergency
service in which the tracing of the origin of the last
call is provided and recorded in case it may be needed later for legal reasons The results ofthe trace are not given to the customer under privacy laws but may be revealed later through proper legal channels
Call Transfer A surcharge phone service, or
capa-bility of a multiline phone system, that allows a call
to be transferred to any other phone on the system Transfers are accomplished by typing in codes and the transfer number, or by keying a transfer button followed by the cal1ee's line Cal1 transfer is com-monlyused in business, and the console often staffed
by a full-time operator or receptionist Callers are not tolerant of cal1s that are incorrectly transferred or ac-cidentally terminated, and it's important that person-nel responsible for transferring calls are well trained
on the equipment and in business etiquette
call tree A diagrammatic representation of call
se-quence information (usage) used for statistical analy-sis and planning See cal1 routing tree
Call Waiting CWO A surcharge or bundled phone
ser-vice that becomes active if a cal1 comes in while the callee is already engaged in a call Call Waiting sig-nals the callee, either by an audio signal or blinking light, that there is another party trying to call, and pro-vides the callee the option of ignoring, terminating,
or holding the current call and then answering the second incoming cal1 This is useful for emergency calls or for ending a casual conversation to carry on with other calls
Cal1 Waiting can interfere with a transmission, or even cut off a call if the line is connected through a com-puter modem Call Waiting can usually be tempo-rarily disabled to avoid this problem, or the modem can be reconfigured to ignore this type of interrup-tion The first option is easier and preferable Infor-mation on how to disable Call Waiting is listed at the front of most local phone directories
Cal1 Waiting for ISDN is specified within ITU-T Q.83 and Q.733 cal1 completion services
Call Waiting illA surcharge or bundled phone ser-vice that combines Call Waiting and Canerill capa-bilities This enables the callee to determine the Caller ill (origination) of a call that is queued and waiting through Call Waiting services The service requires
a Caner ill-capable phone with a display to show the Caller ill data See Call Waiting, Caller ill
Callan, Nicholas J (1799-1864) An Irish priest and
educator who devised a historic induction coil in
1836 He also researched various aspects of electro-magnets, condensors, and batteries See induction coil
callback facsimile A system in which you (1) dial a
cal1back service, (2) key in your callback phone num-ber, (3) identify the documents that are of interest (usually from a numerical list given by a voicemail system), (4) hang up, and (5) wait for a callback-en-abled facsimile machine to automatically dial your fax machine and deliver the documents requested A significant proportion of computer industry techni-cal support and product information is now delivered this way In the future, callback fax systems wil1likely
be superseded by more flexible and economical email document delivery systems
Trang 6phone call through a network that acts as a callback
request A password may be required, and then a
phone number to be dialed is provided to the system
The modem then is set by the computer to dial the
number provided Why do this instead of dialing
di-rectly? This system provides better security, so there
is a record of numbers that have been connected to
the network and data access Sometimes toll charges
are reduced; the toll is billed to the network number
and handled by the business accounting office, rather
than being billed to an employee
Callender Rapid Phone CompanyOne of the
ear-liest automatic switching phone services, established
in England in 1896 by musician and inventor
Ro-maine Callender
Callender, RomaineA Canadian music
teacher/in-strument maker and associate of A Graham Bell,
Callender founded the Callender Telephone
Ex-change Company in Ontario, Canada Between 1892
and 1896, he submitted three series ofpatents for
tele-phone switching inventions He failed in trying to
implement them in Ontario and subsequently traveled
to New York to seek financing and open another firm
Traveling with him were two brothers, George
Will-iam Lorimer and James Hoyt Lorimer, who assisted
him in further experiments The brothers finally
suc-ceeded in developing an automatic switching system
in 1895 They later returned to Brantford, Ontario,
and Callender sailed to England in 1896, where he
formed the Callender Rapid Telephone Company See
Lorimer, George and James
Callender switchA very rudimentary, early
tele-phone switching system developed by Romaine
Callender and the Lorimer brothers in the late 1800s
See Callender, Romaine; Lorimer switch
Caller ID, Call DisplayA phone carrier 'added
value' pay service that provides the call recipient with
the phone number identity of the calling party You
may have to pay local and long-distance Callerill
charges separately In North America, the Callerill
information is usually passed to the receiving phone
between the first and second ring
You need two things to take advantage of Callerill:
a subscription through the phone carrier to the Caller
illservice and a phone or separate device with a
Callerilldisplay See call blocking, Class, ANI
Caller Independent Voice RecognitionAn
auto-mated voice recognition system that can interpret
voice input without being specifically tuned to a
par-ticular caller's voice.Itis useful in phone
applica-tions that accept spoken numbers or commands for
processing a call and in voice recognition word
pro-cessing applications
Caller NameA phone carrier added value pay
ser-vice that takes an incoming Callerillnumber
(assum-ing the call is not blocked), looks it up in a directory
listing database, and transmits the Callerillnumber
and its associated listing, ifit exists, to the recipient's
add-on Caller Name display or to a phone providing
Caller Name display This is not as flexible as a
user-configured system where you can associate any name
but it is very useful for identifying a first-time caller
or stranger (and it may be possible to use them to-gether ifyou have compatible peripherals) See Caller
ill,call blocking
calling cardAremote or off-premises phone service provided by common carriers to allow local and long-distance calls to be charged back to the subscriber's local phone number or other authorized billing num-ber There mayor may not be surcharges associated with such a call The name derives from a wallet card typically issued to the subscriber with instructions and digits to be dialed to gain access to the service In many cases, you don't need the physical card to make the call, but automated phones are becoming preva-lent in which the card is physically inserted in a slot
or swiped through the phone to expedite the process-ing of the call
Bell Canada claims a trademark over the Calling Card name, but the term is widely used in the generic sense, making it difficult to enforce the trademark
calling jackInmanual switchboard systems, the jack that is used by the operator to connect the call that came in through theansweringjack to the circuit for
the subscriber who will be receiving the call
calling number displaySee Caller Name, Callerill calling party, calling stationAperson or entity origi-nating a call See call
Calling Party NumberCPN.Intelephony, a com-mon channel signaling (CCS) parameter in the ini-tial address message that identifies the calling num-ber and is sent to the destination carrier
calling sequenceThe sequence of numbers, letters, steps, and other information needed to connect a call through a traditional phone line or digital computer phone system When calling through a modem, the calling sequence includes not just the number being dialed, but also the parameters for the line, the baud rate, whether it is pulse or tone, the speaker level, pauses, wait for tone to continue with extension num-bers, etc In computer software, the calling sequence may include linking to an address book or other da-tabase and saving statistic information gathered on the call
CallPathA computer telephony integration (CTI) software product developed byffiMfor integrating voice and data communications for telecommunica-tions call centers, thus enabling them to function as more advancedcontact centers CallPath is open
ar-chitecture software supporting multiple computer and telephony switch platforms CallPath can be inter-faced with Web-based applications and other in-house front-end applications JTAPI implementations such
as JavaTel can be run on top of Callpath
In May 2001, Genesys Telecommunications Labora-tories, a subsidiary ofAlcatel, announced plans to pur-chase the Callpath assets with the intention ofwork-ing jointly withffiMto deliver contact center solu-tions based on Genesys interaction management products andffiMDirectTalk and WebSphere plat-forms
callsign, call signIn radio communications, a series
Trang 7Fiber Optics Illustrated Dictionary
of identification characters assigned by local
regulating authorities to every licensed radio
opera-tor or station The callsign identifies the country, and
sometimes also the region of the country One of the
most famous callsigns in radio history is 8XK which
Frank Conrad used from his Pennsylvania garage, and
which was later licensed as the history-making
KDKA radio broadcast station See KDKA
calorie A unit of expended thermal energy - the
amount required to raise the temperature ofone gram
of water by one degree centrigrade (C) from 14.5 to
15.5°C One calorie equals 4.186 joules (Note: a
di-etary calorie is actually 1kilocalorie - 1000 calories)
See calorimeter, joule
calorimeterAninstrument for measuring energy
expended as heat For example, calorimeters can help
assess the power ofa laser by providing a reading on
the amount of heat absorbed by the beam
A calorimeter can be designed in a tower geometry
that includes scintillating tiles The application of
energy in the active scintillator elements produces
light, some of which may be re-emitted and shifted
as to its wavelength with coiled wavelength-shifting
fibers within the tile structure The light can then be
transmitted through an optical fiber to a phototube
or photomultiplier tube where it is converted to
elec-trical energy See calorie, scintillator,
wavelength-shifting
CALS Continuous Acquisition and life-Cycle
Sup-port (formerly Computer-aided Acquisition and
lo-gistics Support) A Department of Defense(000)
strategy for the creation, use, and exchange
ofweap-ons-related digital data
CALSCH The calendaring and scheduling working
group of the IETF See iCalendar
cam A compact digital or analog video camera
in-tended for use in one location for an exin-tended period,
as opposed to a still or video camera that is carried
around with the user to many locations (a few very
tiny cams are intended to be body-worn or carried in
a purse or briefcase) Cams are also distinguished by
having few or no controls other than basic aiming and
focusing capabilities Cams are usually mounted on
small stands or may be hidden within other real or
simulated devices such as clock radios and smoke
de-tectors They may be wired or wireless and are often
interfaced with a computer or a VCR for
transmis-sion or recording of the cam images
Cams are becoming very popoular for
videoconfer-encing, baby monitoring, Internet security, remote
monitoring (children at a day care center or wildlife
that has been released after being fitted with a cam),
and surveillance activities In recent years the price
ofa small, high resolution color camera has dropped
from $600 to less than $100 See camcorder
cam, stump Asmall, high-quality video camera in a
housing that resembles a bottle cap or tiny tree stump
These are favored for sports broadcasting applications
as they can be easily mounted on helmets, stadium
fences, sporting animals (hunting dogs, polo ponies,
etc.) They are also suitable for use on remote
sens-ing platforms and for surveillance applications
CAM 1 carrier module 2 Call Accounting Manager
3 Call Applications Manager A Tandem telephony software interface for linking computers with telephone switches 4 See computer-aided manufac-turing 5 computer-assisted makeup, composition and makeup A WYSIWIG terminal for previewing type composition and page layout 6 See camcorder CAMA See Centralized Automatic Message Ac-counting
camcorder A combination digital or analog video recorder and camera unit Increasingly, consumer camcorders include playback, editing, and special ef-fects capabilities Newer digital camcorders can be used as both digital still-frame and motion recorders and can be interfaced directly with software for scan-ning, image processing, and Web applications Cam-corders may eventually supersede analog video cam-eras and still film camcam-eras, since no film processing
is required, and consumers frequently favor conve-nience over image quality (35mm film is about 16 times higher resolution than current consumer digi-tal systems but digidigi-tal quality is improving steadily) See cam
Cameo Personal Video System AMacintosh-based commercial videoconferencing product from Com-pression laboratories Inc that supports audio, video, and file transfers It works over Switched 56, ISDN, and Ethernet networks Cameo uses a proprietary ClI PV2 compression scheme See Connect 918, CU-SeeMe, MacMICA, IRIS, ShareView 3000, VISIT Video
Campillo See Salva i Campillo, Francesc
campus Aphysical and geographic environment (pri-marily the grounds) associated with learning and/or research facilities, such as universities, hospitals, and some businesses
campus backbone The primary network of wires/ cables that interconnect a campus See backbone circuit Campus Wide Information System CWIS A sys-tem of interactive kiosks and public information sources that provides directories, product or course offerings, maps, calendars, and other general public services of interest to educational institutiotls, busi-nesses, expositions, and shopping complexes CAN 1 Control Area Network 2 See Controller Area Network
CAN in Automation CiA A nonprofit trade asso-ciation founded in March 1992 to provide technical, product, and marketing information to promote and support ControllerArea Network (CAN) technology The association further develops and supports
CAN-related higher layer protocols, including the CAN Application Layer (CAL), CAN Kingdom, CANopen, and internationally recognized standards http://www.can-cia.de/
Canada Machine Telephone CTM One of the ear-liest phone companies to use automatic switching, technology that was developed jointly by George and James Lorimer and Romaine Callender TheLorimer brothers established CMT in Peterborough, Ontario, Canada in 1897, and there produced the first com-mercial Callender Exchange The Lorimers
Trang 8contin-resemblance to the original Callender switching
system The company lost its technical expertise
when James Hoyt Lorimer died, but his brothers
George and Egbert continued to market the products
in NorthtAmerica and Europe Unfortunately, due to
lack ofreliability and long installation times, the
com-pany didn't thrive and was acquired by Bell in 1925
See Lorimer switch
CanadarmA remote manipulator system designed
and made in Canada for the U.S space shuttle
pro-gram The National Museum of Science&
Technol-ogy has constructed a full-size replica and produced
an accompanying video for a traveling exhibit
Canadian Amateur Radio Advisory Board
CARAB Anonprofit consulting group comprised of
members of the Radio Amateurs of Canada (RAC)
and the Radio Regulatory Branch ofIndustry Canada
(IC) CARAB works as a communications liaison
between RAC and IC http://www.rac.calcarab.htm
Canadi.an Association of Broadcasters,
L' Association canadienne des radiodiffuseurs
CAB/ACR Atrade organization founded in 1926 by
13 broadcast pioneers The CAB supports over 500
radio, television, and specialty broadcast providers
in Canada
Canadian Broadcast Standards CouncilCBSC/
CCNR.Anorganization incorporated in 1990 to
en-courage high standards of broadcasting and
profes-sional conduct by private radio and television
broad-casters The CBSC keeps broadcasters informed
about societal issues, administers codes of industry
standards referred by the Canadian Association of
Broadcasters (CAB), and provides information
re-sources to the public http://www.cbsc.cal
Canadian Broadcasting Corporation CBC The
primary broadcasting organization of Canada, CBC
is a public broadcasting service providing television
and radio programming in both English and French
The CBC was initially established in 1936 to ensure
Canadian content in broadcasting CBC's first
tele-vision broadcast took place in 1952, in Montreal In
1966, it began color broadcasting, the first in Canada
to do so SeeANIK., CKAC http://www.cbc.cal
Canadian Business Telecommunications Alliance
CBTA Anational, nonprofit organization
represent-ing over 400 businesses and telecommunications
us-ers in Canada The CBTA supports membus-ers and
fa-cilitates Canada's competitive participation in
tele-communications markets through quality and
inno-vation
Canadian DatapacThe world's frrst public data
net-work which began operating in 1976
Canadian Independent Telephone Association
CITA A national trade association supporting
inde-pendent telephone service providers, founded in
1905 CITA is based in Toronto, Ontario and supports
members in B.C., Ontario, and Quebec CITA
pro-motes the advancement and use oftelephone services
in communities served by its members and represents
its membership in regulatory matters
http:www.cita.cal
Founded in 1958 as the Computing and Data Process-ing Society ofCanada, it became CIPS in 1968 CIPS defines and promotes information processing in Canada and supports the information technology (IT) profession
Canadian Journal ofCommunication CJC
Aschol-arly professional journal that deals with many histori-cal and sociopolitihistori-cal aspects of communications in Canada and abroad
Canadian National Museum of Science & Tech-nology, Musee National Sciences& Technologie
Canada's largest technological museum, located in southeast Ottawa, featuring permanent and special exhibits, traveling exhibits available for loan, school programs, workshops, lectures, publications, and more http://www.nmstc.cal
Canadian Radio Television and Telecommunica-tions CommissionCRTC The Canadian regulatory commission, basedinOttawa, Ontario This impor-tant organization is similar to the Federal Communi-cations Commission (FCC) in the United States in that it allocates frequency spectrums and carries out other commercial and amateur radio and television broadcasting administrative functions
Canadian Satellite Users Association CSUA A trade association ofbroadcasters using Telesat facili-ties and suppliers of goods and services to CSUA voting members THE CSUA sponsors an annual trade convention SeeANIK.,Canadian Space Agency
Canadian Space AgencyCSA One of the more ambitious ofthe CSA's various projects was the Com-munications Technology satellite (HERMES) project which was undertaken jointly with the U.S Canada was to supply the satellite, and the U.S the traveling wave tube amplifier This high power, high frequency, communications satellite project got underway in
1971 and was intended to test direct-to-home broad-casting technology HERMES was successfully launched in 1976 aboard a three-stage rocket The satellite operated for almost twice its expected life-time, almost four years
Canada competes at the international level in space-craft assembly, integration, and testing through its David Florida Laboratory (DFL), west of Ottawa, Ontario, established in 1972 Besides the HERMES satellite, the CANADARM and various ANIK satel-lites have been developed and manufactured at the DFL See ANIK
Canadian Standards AssociationCSA ACanadian, independent, not-for-profit standards-setting body established in 1919 The CSA is a strong participant
in international standards discussions and directions
It engages in a consensus approach to standards adop-tion and provides educaadop-tional services, including pub-lications, conferences, and seminars The CSA oper-ates a Certification&Testing Division and indicates that products or systems have passed a fonnal evalu-ation process at stated levels
The CSA is recognized by the U.S as a Nationally Recognized Testing Laboratory (NRTL), in order to eliminate the need for duplicate testing for products
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marketed in both Canada and the U.S., and provides
assistance to manufacturers marketing to the European
Union
CSA has an official mark recognized as indicating a
product or system that meets certain industry
stan-dards See Standards Council of Canada
Canadian Telecommunications Consultants
Asso-ciationCTCA A Canadian association of
indepen-dent telecommunications consulting professionals
http://www.ctca.ca/
Canadian Wireless Telecommunications
Associa-tion CWTA A trade association representing the
Canadian wireless telecommunications industry,
in-cluding satellite, cellular, and other mobile
commu-nications services
cancelStop aprocess, function, or action On a
copy-ing machine, to abort the current copy if it has not
already gone through the machine and any additional
copies that may have been requested
Ina computer application, to stop or abort the
cur-rent operation or process Control-C (two keys held
down together), sometimes designated as ACor
Ctrl-Cis a very common key code combination for
aborting a process It should be used with care as it
may abort the user right out of the program.Inmany
applications, a Cancel button is provided to close a
dialog or window without carrying out any actions
(when you change your mind), or to stop a process
in progress In some older systems,AYworks in a
manner similar to AC "Zis somewhat related, and
usually less dangerous; it may suspend the current
process (rather than closing it down) and allow you
to carry out other activities, so you can later return to
the original process With Unix system shell
com-mands, a process can be resumed withfg (foreground)
after having been suspended with Al
On phone systems, many services are enabled and
disabled, or canceled, by typing in two or three digit
codes, sometimes followed by a#or*symbol This
applies to services such as Call Forwarding, Call
Waiting, etc It is advisable to cancel or disable Call
Waiting before using a modem on a phone line in
or-der not to be interrupted during a big data transfer
The codes for the subscriber's region for disabling
various services are usually listed at the beginning
of local phone directories
candela(abbrev - cd) A unit of luminous intensity,
originally based upon the quantity oflight generated
by a single candle, it was later more precisely defined
as the quantity of illumination emitted by a black
body heated to the temperature at which platinum
changes from a liquid to solid state See luminous
in-tensity
candlestick telephoneA style of desk phone
popu-lar in the early 20th century that is characterized by
a broad base with a slender, candle-like stem with a
receiver on the top The speaker was usually a
sepa-rate unit, attached with a cord to the stem, which was
hung on the stem when not in use Some versions of
the candlestick were adapted to hang on a wall, with
a solid or accordian-style mounting bracket (e.g., the
Western Electric accordian candlestick)
CAP 1 See carrierless amplitude and phase modu-lation 2 See Cellular Array Processor 3 See Com-petitive Access Provider
Capabilities Exchange In Data Link Switching (DLSw), a Switch-to-Switch (SSP) control message that describes the characteristics of a sending Data Link Switching (DLSw) router to allow inter-router information exchange and to provide greater compati-bility among different implementations See Data Link Switching
capacitance(symb - C) The ratio between an elec-tric charge and the resulting change in potential, or the time integral ofthe rate offlow ofelectric charge, divided by the related electric potential Capacitance
is measured in farads See capacitor, capacity, Ley-den jar
capacitorAnarrangement of conductors separated
by dielectrics, which may be fixed or variable, de-signed to store electrical energy Capacitors are used
in a wide variety of electronic devices See capaci-tance, capacity, condenser, Leyden jar
Historic Capacitor
From Leyden jars to tiny solid state components, various means ofstoring electrical energy have been devised over the years This historic capacitor from the American Radio Museum illustrates how much ca-pacitors have changed, as most electronic caca-pacitors now resemble stubby battery housings.
capacity1 The maximum number of objects or oc-cupants that can be contained on or in a system or environment under normal operating conditions (such
as load, theater, or bridge capacity) 2 The maximum information-carrying capability ofa communications system The unit of capacity varies from system to system; on a network, it might be described gener-ally in terms ofnumber ofusers, or more specificgener-ally
in terms of a calculation based upon speed, access,
or load upon a CPU, or it may be based upon trans-fer rates for cells or frames
Capasso, Frederico(1940s- )AnItalian-born Bell Laboratories scientist who has made numerous con-tributions to electronics, particularly photonics Capasso has contributed to bandgap engineering in-novations in optoelectronics, semiconductor, and solid state electronics and, in 1994, co-invented the quantum cascade laser (QC laser) Capasso has
Trang 10previously observed in nature and that are based on
relative thickness and proximity, rather than
chemi-cal composition See quantum cascade laser; Townes,
Charles H
Cap'n Crunch Aninfamous phone hacker (phreaker)
from the 1970s and 1980s, John T Draper (ca 1943- )
adopted this handle (techie nickname) and served a
sentence for illegal (albeit creative) tampering with
the phone system using technology and tones to make
unpaid-for long-distance calls His adventures and
discoveries resulted in the phone company making
some significant changes to their technology and
plugging a number ofsecurity loopholes Some ofhis
exploits are described in Stephen Levy's book
Hack-ers and in a 1971 article in Esquire Magazine entitled
"Secrets of the Little Blue Box."
Legend has it that John Draper's monicker stems from
a whistle he acquired from a cereal box of the same
name, one which produced a 2600-Hz tone which
could be processed by the phone trunk system as a
hangup signal when blown into the telephone
mouth-piece (a tip he received from a blind fellow) The line
would stay connected, but the call would not be billed
This type ofcaller signaling is not possible on newer
phone systems which use out of band signaling,
be-cause the voice conversation and the phone control
signals are on different circuits
Draper became associated with Steve Jobs and Steve
Wozniak and wrote the first word processor for the
Apple II computer, called TextWriter (which became
EasyWriter)
In 1985, Draper wrote a series of Amiga computer
technical tutorials, which he distributed free over the
net, at a time when the Amiga was an
underappreci-ated new entrant to the field ofmultimedia
microcom-puting He now creates computer intrusion detection
systems See blue boxing
Capstone chipAhardware security device that uses
the same SKIPJACK cryptographic algorithm as the
Clipper chip It incorporates a Digital Signature
Al-gorithm (DSA), a Secure Hashing AlAl-gorithm (SHA),
a public key exchange, and various associated
math-ematical algorithms It's a complex, powerful system,
requiring almost 1Gigabyte on an automated design
system to set up the chip The chips are being installed
in various electronic devices for the U.S Defense
Messaging System See Clipper chip, Pretty Good
Privacy
Capture Division Packet AccessCDPA A
packet-oriented cellular communications network
architec-ture designed to handle constant bit rate (CBR) and
variable bandwidth multimedia telephony
applica-tions such as videoconferencing Unlike some other
protocols, CDPA is bandwidth-adaptable; it can
sup-port increased channel access for individual users for
briefperiods
capture effect, captive effectIn radio
communica-tions, signals often compete with one another if the
frequencies are very similar or if two stations are
coming in with approximately similar strength In
amplitude-modulated (AM) transmissions, the two
and it's hard to make out what is being heard In fre-quency-modulated transmissions (FM), the receiver will filter out the weaker signals, resulting in the cap-ture ofthe weaker signal and the exclusive broadcast-ing of the stronger one If the signals are equal in strength, the receiver may switch back and forth be-tween the two, but it won't play them both simulta-neously as in AM
capture ratioThe capability of a tuner to reject un-wanted transmissions (other stations, interference) that are on the same frequency as those desired The capture ratio is expressed in decibels, with a lower figure indicating better performance
CAR computer-assisted retrieval
car phoneA cellular communications unit installed
in a vehicle While handheld, battery-operated sys-tems are often calledcar phones, the phrase more
properly distinguishes larger units that use power from the car's battery and connect to an antenna physically attached to the car (the center of the roof,
or elsewhere) Generally they consist of two parts, a trunk or below-seat unit, and a handset Car phones generally have higher power and better transmission than handheld cellular phones, although they lack the convenience of portability See cellular phone, mo-bile phone, AMPS
carbon dioxide laser,COllaserA source of laser illumination based upon gaseous molecular action
Anammonia-based infrared laser was first described
in a patent application in 1956 by R Dicke Carbon dioxide lasers were developed by A Javan in the early 1960s
From signaling and spectroscopy to welding, steel-cutting, etching, and delicate surgery, the carbon di-oxide laser is suitable for hundreds of applications where power and precision are important.Ithas even been shown capable ofhalting infections and prevent-ing extended tissue damage that could require am-putation
Early in 2002, Coherent Photonics Group announced that they had developed the first industrial Q-switched
CO2laser The laser emits high-energy, high-repeti-tion, narrow pulses suitable for micromachining/drill-inglPC board applications
A basicCOt!aser can be built in a lab with off-the-shelf parts Note,CO2lasers generate high-energy beams that can cut through steel Safety knowledge regarding assembly and use is essential See helium-neon laser, laser history
carborundumA substance with rectifying proper-ties that was used in early radio wave crystal detec-tors Unlike the popular galena, which required very delicate contact and tuning, carborundum could be clamped tight and sealed firmly within the detector unit, making it suitable for field work and rough han-dling Much of the pioneer work on carborundum detectors was done by H Dunwoody of the U.S Army, who received a patent in 1906
carcinotron Anelectron tube-based backward oscil-lator designed to generate extremely high frequency (EHF) signals See magnetron