Fiber Optics Illustrated Dictionary - Part 39 docx

A unit of information in data networks such as Frame Re-lay systems.. For example, in video games, it is very common to store a wide, ver-tically narrowpanoramic landscape in a frame buf

Fiber Optics Illustrated Dictionary

offorce in a magnetic field taken as a group(symb

-B) When expressed in terms ofdensity per unit area,

it is calledfluxdensity (symb - D)

fly-byn.A representation ofmovement from a point

ofview above the ground, commonly used in

anima-tions, especially video games with flight simulation

Fly-by animations give a wonderful sense of being

inside the scene that is imaged NASA has produced

some wonderful fly-by animations ofthe surfaces of

other planets such as Mars Satellite geophysical data

make it possible to create fly-bys of Earth's surface

right down to individual buildings and streets

Vir-tual reality fly-by simulations are startlingly real, with

participants ducking moving images so as not to be

hit See virtual reality

fly-page See banner

flyback retrace.Ina cathode-ray tube (CRT), the

movement of the electron beam tracing the image on

the screen from the end of the trace to the beginning

where it starts over on the next line Flyback is

usu-ally associated with a blanking interval in which the

beam is turned off so as not to interfere with the

im-age already displayed There is more than one type

of flyback on a monitor The flyback associated with

scanning each line is similar to the line feed and

car-riage return on a typewriter, in that the scan finishes

at the end of one line and flies back to the next line

down (or two lines down in interlaced screens) and

the beginning of the subsequent line, in a zigzag

(sawtooth) pattern The other type offlyback is when

the full video frame is finished, the beam is at the

bottom or last line of the screen and then flies back

to the top or first line of the screen (This example

assumes a typical CRT in which the scanning is left

to right and top to bottom.) See blanking, frame

flying erase head Amechanism on prosumer and

in-dustriallevel VCRs and camcorders that erases

pre-viously recorded video traces that might otherwise

interfere with new information being recorded on top

of the same section This head is typically found on

systems that support insert editing Rainbows and

other undesirable artifacts are thus avoided

flytrap A fIrewall or other security system that logs

unauthorized attempts at access to provide

informa-tion that can help identify or apprehend the intruder

flywheel 1 A wheel that works with other

mecha-nisms to smooth out and reduce inconsistencies in the

rotational speed of the equipment 2 A wheel that is

used with other mechanisms, whose purpose is to

store kinetic energy Flywheels are often coupled with

power generators to continue the motion when the

generator mechanism slows or is idle

flywheel effectIna transmission that experiences

fluctuations, the maintenance ofa steadier, more

con-sistent level ofcurrent, information, or oscillation by

physical or logical means Analogous to the function

of a flywheel

FM 1 fault management 2 See frequency

modu-lation

FM broadcasting Transmission through frequency

modulation technologies on approved FM

frequen-cies with the appropriate FM broadcasting license In

the United States, FM stations are spaced at 0.2kHz intervals, ranging from 88.1 to 107.9 kHz Low power

FM broadcast signals are used for mobile intercoms, indoor intercoms, monitors, and cordless phones See broadcasting, FM broadcasting, frequency

modula-tion

FM transmitterInits basic form, an FM transmit-ting system includes a microphone, a circuit, and a frequency modulating (FM) transmitter In more so-phisticated forms, it includes the various commerciaV industrial transmitters costing thousands of dollars for broadcasting from licensed radio news and en-tertainment and other FM communications stations Building simple FM transmitters in the 88- to 108-MHz frequency range is a very popular hobbyist in-troduction to electronics With current technology, it

is possible to create very compact, working FM trans-mitters for under $30, to broadcast a few hundred feet

or even up to two miles under good conditions Be-fore conducting hobbyist experiments with low power FM transmitters, it is important to learn the various Federal Communications Commission (FCC) restrictions on broadcasting, and to honor laws pro-tecting the safety and privacy ofindividuals

FMAS 1 Facility Maintenance and Administration System 2 Fund Management Accounting System FMV See Fair Market Value

FNB SeeFiberoptics NewsBriefs.

FNC See Federal Networking Council

FNEWS A fast full-screen news reader for UNIX, ALPHA-VMS, and VAXNMS systems, similar to NEWSRDR and ANU-NEWS News articles for groups are cached and dynamically loaded Version 2.0, released in 1995, included access security for newsgroups and removed the limits on the size and number ofnewsgroups that could be loaded FNEWS

is a commercial shareware product

Fnorb ACORBA 2.0 Object Request Broker (ORB) written in Python and a tiny bit of C by the Hector Project participants at the CRC for Distributed Sys-tems Technology at the University of Queensland, Australia Fnorb supports CORBA datatypes and full implementation ofIIOP It is freely distributable for noncommercial use See CORBA, ORB

FNR 1 Faculty Network Resources 2 fixed network reconfiguration Configuration ofan existing network with static transmission lines to support upgraded services or a wider variety of services, often used as

an interim solution instead of completely replacing

a network

FNS Fiber Network System/Service

FO-2 Acommittee ofthe Telecommunications Indus-try Association (TIA) developing physical-layer test procedures and system design guidelines and speci-fications for distributors and users offiber optic com-munications technologies Since 2000, plenary meet-ings have been held jointly with FO-6, a TIA com-mittee on Fiber Optics

FOA 1 fiber optic amplifier 2 See Fiber Optic As-sociation, Inc 3 First Office Application Testing of systems within an office application once in-house testing is complete or nearly complete Most of the

what is now sought is relevance and feedback from a

real-world installation.Insoftware development, it

is known as beta testing.

FOeFirm Order Confirmation Aproduct or service

agreement confirmation document

foam dielectric cable Acable assembly that utilizes

foam as a nonconducting medium around the

con-ducting medium to reduce noise and increase

trans-mission speed Foam dielectric cables are sometimes

substituted for air dielectric They don't quite meet

the performance characteristics ofthe best air

dielec-tric cables, but they have advantages such as good

moisture-resistant properties and no requirement to

pressurize the cable housing See air dielectric cable

focal length (symb - f) In a viewing or recording

mechanism, the distance from the focal point on the

surface being viewed or recorded to the center of a

lens or surface of a mirror, as on a camera

focus n 1.Inan optical viewing or recording

mecha-nism, the point at which rays diverging or

converg-ing from a surface intersect in the mechanism

(through a lens or on a mirror) to produce a clear,

un-blurred image ofthe surface 2 In a projected image,

the point on the projection surface in which the rays

converge to produce a clear, unblurred image 3 In a

color cathode-ray tube (CRT), convergence of the

electron beams on a precise point on the coated

in-ner surface of the glass to provide a clear image on

the front surface of the tube 4 In human vision, the

point at which the distance ofthe object being viewed,

the angle of the individual parts of the eye, and the

angle of two eyes are correlated so that the image

appears clear and unblurred 4 Center ofattention or

activity

focus group A group organized to concentrate on or

discuss a specific issue

FODfax-on-demand

FODBSee Fiber Optic Data Bus

FODTESee Fiber Optic Data Transmission

Ex-periment

FOLDOe Free Online Dictionary of Computing

FOLDOC is a popular, searchable resource

contain-ing over 13,000 concise definitions related to

com-puting topics FOLDOC was established in 1985 and

is edited and copyrighted (1993) by Denis Howe The

information is distributed for use under the terms of

the GNU Free Documentation License

http://www.foldoc.org/

FOLMSee fiber optic lever microphone

FOLSSee Fiber Optic LAN Section

FOMSee fiber optic modem

footprint 1.Anarea or impression on a surface

com-prising a more or less contiguous region of contact

with the bottom of some object or signal 2 The desk

space or floor space taken up by a piece of furniture

or equipment, usually considered the area of actual

contact, or the area ofcontact plus everything within

its boundaries, and the small area surrounding it,

which may be taken up by connectors or protruding

knobs 3 The terrain or surface of the Earth over

which a transmission signal can be received

Atrans-cal footprint, as a transmission tends gradually to decrease in intensity (this may be shown by contour lines on a map or chart), and there is often no defi-nite cutoff point, unless specified as signals below a certain level 4.Anaudit trail or traces left by a trans-action or process which has concluded or aborted 5 The resource requirements ofa system For example,

the Amiga is said to have a small systemfootprint

be-cause it can adroitly handle preemptive multitasking, sound, and simultaneous animated graphics in a Megabyte of memory on a 25- or 40-MHz processor forecasting Predicting future events, usually based

on an analysis and evaluation of past events Fore-casting is needed in all areas of telecommunications

to choose technologies that are powerful and eco-nomical and that won't be quickly outdated It is also used by system administrators to configure and tune systems to handle predicted needs and traffic loads Businesses use forecasting to select local area net-work topologies and net-workstations, and by managers

to organize employee loads and working schedules See erlang, queuing theory, traffic management Foreign Agent A service enabling nodes to register

at a remote location, providing a forwarding address

to a home network in order for forwarded packets to

be retransmitted to the remote location Foreign agents are an important aspect ofMobile IP systems Foreign Exchange Service FX, FEX, FXS A ser-vice that connects a subscriber's telephone to a re-mote exchange as though it were a local exchange Commercial vendors provide a variety ofmultiplex-ing interface cards to telecommunications carriers to facilitate provision of subscriber Foreign Exchange Services

Forrester, Jay Wright (1918- )Acomputer pioneer who investigated memory devices for computers in the 1940s and 1950s while working on the construc-tion ofthe Whirlwind computer at the Massachusetts Institute of Technology (MIT) Forrester was at the forefront oftransition technology from analog to digi-tal systems and invented core memory with assistance from William N Papian in 1951

FORTH1 Foundation ofResearch and

Technology-Hellas 2 Fourth Generation Language.An exten-sible, high-level programming language typically used in calculators, robotics, and video game devices

FORTRANFonnula Translation Ahigh-level

com-puter programming language that was commonly used in the 1980s for math-oriented applications, and from which BASIC has derived many ofits syntacti-cal characteristics.Itgrew partly out of conceptual ideas and examples of reusable code promoted by Grace Hopper, and further from the encouragement

of John Backus that a language be developed that could express and solve problems in terms of math-ematical formulae With the advent ofother languages such as BASIC, C, C++, Perl, and Java, the use of FORTRAN is declining

forum Discussion group, private or public meeting, judicial assembly Electronic forums are common on the Internet See USENET

Fiber Optics Illustrated Dictionary

forum, online Anetwork virtual environment for

dis-cussions Internet Relay Chat (IRC) channels,

USENET newsgroups, discussion lists, and various

meeting places on Web sites are examples of global

forums where topics are ardently and enthusiastically

debated When forums include celebrities, they are

usually moderated to keep the questions and

com-ments to a manageable level

Forum for Responsible and Ethical Email FREE

Anorganization for education and assistance to

in-dividuals and groups seeking to balance the need for

freedom to send email and the need for respecting the

personal privacy and economic rights ofemail

recipi-ents FREE sponsors an informational Website,

dis-cussion groups, and provides up-to-date news on

spam-related issues in the media and the legislature

http://www.spamfree.orgl

Forum of Incident Response and Security Teams

FIRST Aglobal coalition established in 1990 to

fos-ter the exchange of information and response

coor-dination among computer security teams Participants

come from a variety of academic, commercial, and

governmental organizations Part of the motivation

for establishing FIRST came from the 1988 events

associated with the spread of the Internet Worm,

which made it clear that economic damage and loss

of productivity were very real threats to the global

Internet and that coordinated efforts to respond to

such incidents would be more efficient than the

hit-or-miss response to the spread of the Internet Worm

FIRST fosters cooperation among technology and

security experts and facilitates research and

opera-tional improvements to support secured networking

See Computer Incident Advisory Capability,

Com-puter Emergency Response Team, WORM, virus

http://www.frrst.orgl

forward error correction FEC A means of

ensur-ing a transmission in advance by duplicatensur-ing

infor-mation or otherwise improving the chances ofits

be-ing received the first time For example, characters

or groups ofcharacters may be sent two or more times

(calledmode B in amateur radio transmissions)

ac-cording to a predetermined arrangement Repeating

characters, or groups of characters, in data

transmis-sions gives a receiver an opportunity to compare the

groups and, if any of the information doesn't match,

request a retransmission The basic idea is to

mini-mize the back-and-forth nature of handshaking to

speed a transmission while still giving information

that may be used to check the integrity of the

infor-mation being received

Forward Explicit Congestion Notification FECN

In a Frame Relay network, a bit used to notify an

in-terface device to initiate congestion-avoidance

pro-cedures in the direction of the received frame See

Backward Explicit Congestion Notification

Forwarding Equivalence Class FEC In

Multipro-tocol Label Switched (MPLS) networks, the FEC is

a networking categorization scheme associated with

packet-forwarding Aspecific FEe includes

destina-tion address informadestina-tion and may include service

information FEe details are managed within a

router's forwarding information base (FIB) See Multiprotocol Label Switching

FOS2 See Fiber Optics Sensors & Systems FOSS 1 Facilities Operations Support Services Ser-vices at the Stennis Space Center 2 See fiber optics sensing system 3 Future of Space Science FOT Fiber Optic Terminal Aconnection point or de-vice at which a fiber optic circuit connects to a cop-per wire circuit

FOTS fiber optic transmission system

Foucault test A type of optical null test (a test using the instrument itself) for determining the optical qual-ity ofa spherical surface relative to the center ofcur-vature ofthe component with a point light source See Dall test, Ronchi test, star test

Foucault, Jean Bernard Leon (1819-1868) A French physicist best known for his studies of the speed of light and the rotation of the Earth through the use ofpendulums, Leon Foucault also developed

a gyroscope (1852) and a mechanical telegraph In

1850 he was awareded the Copley Medal by the Royal Society of London for his work on the rela-tionships between heat, magnetism, and mechanical energy He also studied photographic processes and vision See knife-edge focusing

Fourier, Jean Baptiste Joseph (1768-1830) Fourier,

a French mathematician and lecturer, discovered in the early 1800s that the superposition of sines and cosines on time-varying periodic functions could be used to represent other functions He made practical use of these techniques in the study of heat conduc-tion, work that was developed further by G S Ohm

in the 1820s in his mathematical descriptions ofcon-duction in circuits Work on linear transformation mathematics that predated Fourier's publications was carried out by Karl F Gauss but went unpublished until after Fourier's descriptions See Fourier trans-form

Fourier analysis A means of representing physical

or mathematical data by means of Fourier series or Fourier integrals

Fourier transform A linear mathematical data ma-nipulation and problem-solving tool widely used in optics, transmissions media (antennas), and more The superposition ofsines and cosines on time-vary-ing functions can be used to represent other functions,

in other words, to represent the data from another point of view The result of such a transformation is

to decompose a waveform into subsets of different frequencies, which together sum up to the original waveform In this way, the frequency and amplitude can be separately and more easily studied

A rudimentary application of Fourier series calcula-tions were used to utry nderstand planet orbits in Greek times Their development was in part ham-pered by the Greeks' mistaken assumption that the Earth was the center of the universe

Fourier transforms differ from wavelet transforms in that they are not localized in space; however, they also share many common characteristics Named after J.BJ Fourier See discrete cosine transform, wave-let transform

sion of a Fourier transform was developed in 1965

by Tukey and Cooley Itsubstantially reduces the

number of computations needed to do a transform,

hence the name FFT computations are used in many

types of imaging applications (e.g., filtering a 3D

image to display a 2D interpretation)

fox messageA test sentence that includes all the

let-ters ofthe English alphabet, commonly used to verify

if all letters of the English alphabet in a device or

coding system are present and/or working correctly

Familiar to most as "THE QUICK BROWN FOX

JUMPS OVER THE LAZY DOG" (which may then

be repeated as all lowercase, as needed)

FPLMTSSee Future Public Land Mobile

Telecom-munication System

fpsSee frames per second

FPUSee floating point unit

FRASee Fixed Radio Access

fractalAterm popularized by Benoit Mandelbrot to

describe his geometric discoveries and descriptions

of structures that can be described and reproduced

as mathematical formulas and have the

character-istics of self-similarity in increasingly fine degrees

of detail

Fractal concepts have since permeated almost every

aspect ofcomputing, especially computer image

dis-play, compression, and reconstruction Fractal

geom-etry provides a means to model surprisingly complex

and natural-looking structures with simple

math-ematical formulas See theFractal Geometry

ofNa-ture by Benoit Mandelbrot.

Fractal Image FormatFIF A proprietary image

compression format developed by Michael Barnsley

and Alan Sloan, who together founded Iterated

Sys-tems, Inc to exploit the technology Very high rates

ofcompression are possible The technology is

asym-metric - it takes a while to compress the information,

but it decompresses relatively quickly See fractal

transform

fractal transform, fractal compressionA

resolu-tion-independent, lossy image compression

tech-nique providing a high degree ofperceptual

similar-ity with excellent compression results Fractal

com-pression works by storing image components in terms

ofmathematical algorithms, rather than as individual

pixels of a particular location and color The

organi-zation ofthe image is evaluated for its intrinsic

char-acteristics ofself-similarity, and those charchar-acteristics

are coded so they can be reproduced by repetitions

in increasingly fine detail, up to the resolution of the

output device

With their excellent image fidelity and high

compres-sion ratios, the trade-offin fractal comprescompres-sion is the

time it takes to encode or decode and display the

de-compressed image With faster processors, this is

be-coming less of a limitation See lossy compression;

discrete cosine transform; Fisher, Yuval; JPEG;

Man-delbrot, Benoit; wavelet transform

fractals, fractal imagesAterm borrowed from

frac-tal geometry to describe visual images that have

rec-ognizable visual and mathematical characteristics of

from the rendering of fractal formulas Colored fractals can be beautiful, and they adorn many cal-endars, posters, and t-shirts Many familiar fractal for-mulas have been given names, such as Julia Set, Man-delbrot Set, etc See ManMan-delbrot, Benoit

FRAD See Frame Relay access device

fragmentation1 State ofbeing broken up, separated into units or groupings, having lost connections or cohesiveness, or physically or logically separating over time 2 In hard drive storage, fragmentation is

a gradual process of the available or used areas of a drive becoming smaller and more widely dispersed When information is stored on a hard disk or other similar directory-based system, files are placed where there is room on the drive and sometimes spread over

a number ofareas on the drive When a file is deleted, its directory entry is removed and the space it occu-pied becomes free for other files However, over time (especially with a lot of disk activity), the free areas get smaller and farther apart, and files stored on the drive need an increasing number ofsections and links

to keep track This fragmentation slows down the sys-tem It is sometimes advisable to defragment or

"defrag" a drive to optimize the tables and file data locations Some operating systems have built-in utili-ties for rebuilding a drive or system It is important that sufficient memory and swap space are available

on a system before defragmenting a drive, and it is highly advisable to back up the data first

frame1 Abounded visual or logical unit or block of related information, sometimes delimited with visual

or binary flags or markers A frame is sometimes a natural unit, as in a cyclic event in which the infor-mation repeats in some general sense (though the con-tent may vary), and sometimes it is an arbitrary unit, chosen for convenience or by convention 2 Aphysi-cal unit, border, containment area, skeleton (frame-work), or inclusive extent 3 A full-screen perceiv-able image on a monitor or TV screen consisting of the sum of all the sweeps of an electrongunduring a full cycle of oscillations across the screen 4 A unit

of information in data networks such as Frame Re-lay systems 5 A contained group of infonnation on

an HTML layout, such as a Web page 6 A housing

or support structure for components or wiring See distribution frame, rack

frame, dataIn most networking architectures, a frame is a group of data bits of a fixed or variable size, often in a specified format It is common for frames to be organized into two general types: those which carry signaling, addressing, or error detection! correction information, and those which carry the contents of the communication itself (sometimes called payload), although even these are sometimes combined The format and organization ofthe frames are defined by a data protocol, and there are many general purpose and specialized protocols in use, most not directly compatible with one another Interprotocol frame traffic can be carried or tunneled through other protocols or can indirectly communicate through conversion agents or filters

Fiber Optics Illustrated Dictionary

Frames are organized into larger units comprising a

communication and then may be sent together to the

destination, or they may be disassembled, sent along

different paths, and reassembled at the destination

Frames may also beencapsulated, wrapped in an

outer envelope, to carry them through a system that

requires another format or to tunnel through a

sys-tem without having the contents of the encapsulated

package changed in any way It is then

de-encapsu-lated at the exit point or at the destination

When frames carry different types of data, such as

graphics in one and sound in another, they are

some-times sent simultaneously through separate wires or

data paths and reassociated at the receiving end, as

in videoconferencing In these situations,

synchroni-zation or alignment of information is important and

information for achieving this may be included See

Frame Relay, Frame Relay frame format, protocol

frame, distribution A wiring connection physical

supporting structure See distribution frame

frame, video In video displays that cyclically sweep

the full screen to create an image, a frame is the

ex-tent of the sweep that is required to cover the full

screen In the NTSC system prevalent in North

America, the sweep is 29.97 frames per second and,

on an interlaced screen, is further subdivided into two

sets offields (all odd lines or all even lines) The

for-mats that are common in Europe (pAL, SECAM)

dis-play at 24 or 25 frames per second

It is important to time the frame presentations at a

broadcast station, so that news briefs, commercials,

and regularly scheduled programming can be

orga-nized into precise time slots NTSC displays are

generally 525 scanlines, though not all the bottom

scanlines may be visible on the screen European

stan-dards are 625 lines A frame isanimportant unit in

video display not only for physical synchronization

of the signals, but also because the rapid sequential

presentation of still frames creates the illusion of

movement, and the properties of this illusion must

be taken into consideration ifcreating still-frame

ani-mation sequences See station clock See television

signal for a chart of common formats

frame alignment signal FAS.Inframe-based

trans-missions, a sequence ofbits intended to provide

fram-ing alignment information for synchronization

pur-poses In other words, it provides the necessary

in-formation, usually at the head of a sequence of

frames, for the receiver to synchronize itselfwith the

incoming signal The signal may also include status,

control,anderror-related bits The bits following the

frame alignment signal are often allocated to more

specific alignment or configuration tasks (e.g.,

chan-nel setup), and thereafter there is usually information

content

frame buffer A storage area used for

preconstruct-ing digital images in order to facilitate the quick

dis-play of those images, especially if they are to be

displayed one after another, as in a sequence of

ani-mation frames The image in the frame buffer is not

necessarily displayed all at once For example, in

video games, it is very common to store a wide,

ver-tically narrowpanoramic landscape in a frame buffer

and to display only a portion of the scene at anyone time Then, as the characters in the game move along the landscape, the display scrolls smoothly to right

or left, without display artifacts such as flicker or jumping that may be caused by disk reads or off-screen reconstruction ofthe image Frame buffers are commonly used for high-speed, high-resolution ap-plications such as computer animations, arcade games, and video walls See frame store

Frame Check Sequence FCS A mathematical al-gorithm that derives a value from a transmitted block ofinformation and uses the value at the receiving end

of the transmission to determine whether any trans-mission errors have occurred

FCS is used in bit-oriented protocols such as SNA SDLC to determine ifsent and received messages are the same For example, in SDLC the two-byte (16-bit) FCS field includes a cyclic redundancy check (CRC) value used to assess the validity of the re-ceived bits

frame grabber A computer hardware/software pe-ripheral device designed to capture and digitize a frame, or series of frames, from a continuous signal, usually from an NTSC source (a frame-based video signal) The signal generally comes from live video, laserdisc, or prerecorded tape.It is sometimes called

a video capture board or video digitizer The faster a frame grabber can capture frames, the more true to the original signal a playback of the grabbed frames will appear Generally speeds ofabout 24 frames per second are required for a video animation to appear natural to the viewer See frame buffer, sampling frame merge 1 Over frame-based media, a stream merge 2.Ina Frame Relay network, frame merge can be used as a way to forwardIPpackets or por-tions of packets inside a frame, rather than on an in-dividual cell basis, to improve the scalability of a network while avoiding problems with scaling

vir-tual circuits (VCs) 3.Frame merging is useful in cases where data streams are coming from more than one source, but the software can only handle one in-put stream at a time.Inthese cases, there are utilities available to merge the data streams in various ways, depending upon the type ofdata that is being received and how it is intended to be processed 4 The phrase

frame merge is sometimes loosely used to refer to

convergence ofdata and telephony services for com-panies that are seeking ways to integrate their busi-ness telephone services with their data services on

the same permanent virtual circuit (VC)

Data-tele-phony convergence over Frame Relay is a better way

to describe this process

frame modeInvideo image capture, a mode that cap-tures a full frame of scan lines more or less simulta-neously in contrast to most desk scanners, which cap-ture a line or block of the image at a time Full frame images preserve image integrity but also take more storage space than some modes Most digital cameras are frame mode capture devices See field mode frame rate, video The speed at which a series of images is presented or a screen ofvisual information

sistence ofvisionin human perception, individual still

images presented at about 20 frames per second or

faster give the illusion of motion At speeds of over

30 frames per second, no substantial improvement in

the animation quality is perceived by most people

Motion picture film is usually displayed on 35mm

projectors at 24 frames per second Home 8mm and

Super-8mm projects are somewhat variable around

20 to 24 frames per second, since most have dials to

speed up or slow down the film transport rate

North America TV is broadcast at about 30 frames

per second.(Inactual fact, due to differences between

black and white and color technology, the rate is

closer to 29.97 frames per second.) On various

Eu-ropean systems, such as PAL and SECAM, broadcast

frame rates are 24 or 25 frames per second

On computer systems, frame rates vary with the

soft-ware that is creating the frames or with the softsoft-ware

playing the frames Smaller video windows can be

played back faster than large ones, as they take less

time to compose and require less computing power

to display Displays of 256 colors also refresh faster

than 24-bit displays (-16.9 million colors), although

refresh will vary with the system speed and type of

graphics card used On systems less well adapted to

video, rates may vary from 20 to 30 frames per

sec-ond

Videoconferencing systems running over analog

phone lines may refresh only at frame rates of 5 or

10 times per minute, as the voice-grade lines and

mo-dem create a bottleneck On ISDN and other digital

lines that run at faster rates, 20 or more frames per

second may be possible, depending upon the type of

system and the size of the image window See drop

frame, MIDI time code, SMPTE time code

Frame Relay, Frame Relay networkFrame Relay

is a networking connection option often selected by

smaller businesses as a cost-effective way to set up a

reasonably fast and powerful wide area network

(WAN) or local area network (LAN) that can connect

with public networks Frame Relay can be used across

Integrated Services Digital Network (ISDN) and a

number of other interfaces to interconnect multiple

virtual LANs at lower rates than the cost of leased

lines Standardization efforts for the technology were

initiated in the early 1980s and continued for a

num-ber of years

In1990 and 1991 vendors formed associations to

fa-cilitate development and deployment of the

technol-ogy Viable commercial implementations began

emerging in the early 1990s

Frame Relay is a connection-oriented,

packet-switch-ing protocol designed to provide virtual circuits (VCs)

for interconnections within the same Frame Relay

net-work Virtual circuits may be permanent or switched

(similar to Ethernet) Permanent virtual circuits

(PVCs) are more prevalent, but switched virtual

cir-cuits (SVCs) are of increasing interest

Frame Relay evolved from and is somewhat

simpli-fied over X.25 For example, Frame Relay is

con-cerned with packet delivery without sequence and

times lower cost by trading offerror correction at the network level (Error correction can be implemented

by intelligent user terminal equipment, depending upon needs.) Frame Relay has been shown to work

in practical situations up to almost 50 Mbps

Frame Relay operates at the physical (PRY) and data link layers of the Open Systems Interconnect (OSI) reference model It is implemented as a Layer 2 pro-tocol The physical interface can interconnect mul-tiple remote networks through Frame Relay switches

Frame Relay can transport a number ofencapsulated

~~:!Ss::~::s:::'p:::::::: ::i::t:~:e:::~ ~.

nection status of the link In a Point-to-Point (PPP) system, Frame Relay framing is treatedasa dedicated

or switched-bit-synchronous link See Asynchronous Transfer Mode, cell relay, Data Link Connection Identifier, framing bits, and additional entries pref-aced by Frame Relay

Frame Relay access channelAuser access channel across which Frame Relay data travels The access channel specifies the physical layer interface speed

of date terminal equipment(DTE)and data commu-nications equipment (DCE) An access channel may

be categorized as unchannelized, channelized, or frac-tional When the entire DS-3/TIIEI is used at speeds

of 45/1.536/1.984 Mbps, respectively, as a single

channel, it is considered to be unchannelized When

DS-3/TllEl lines have one or more channels oper-ating at aggregate speeds not exceeding those just listed for unchannelized transmissions, they are

con-sidered to be channelized, with the channel as any of

Ntime slots in a given line In TIIEl, consecutive or

nonconsecutive time slots are grouped as Nx56,64

Kbps/Nx64 Kbps whereN=1 to 24 or 1 to 30 DSO time slots per channel, respectively, and are

consid-eredfractional.

Frame Relay access rateThe data transmissions rate ofthe Frame Relay access channel.Itis the maximum rate at which the user can insert data into the Frame Relay network

Frame Relay access deviceFRAD Another name for the switch, router, or other network device that assembles and disassembles Frame Relay frames as they are transported through a system When data frames are sent over a Frame Relay network, they are packaged with various types of information, often at the beginning and end of the block of frames, and unpackaged again, often at the access point to the des-tination system to recover the structure and contents

of the original communication

Frame Relaying bearer serviceFRBS A service providing bidirectional transfer of service data units (SDUs) from one reference point to another, retain-ing the order offrames FRBS trades offsome aspects

of error processing (e.g., acknowledgments) for speed A local label facilitates device identification over virtual connections

Frame Relay cloud AFrame Relay network that is shared among a small number of participating

Fiber Optics Illustrated Dictionary

subscribers in order to get the benefits of the

tech-nology at a lower cost It is a suitable option for

smaller businesses that do not have high networking

demands but would like higher speeds than are

avail-able through dialup modem connections, for example

The system can handle a firm's voice and data

com-munications needs As data passes through the cloud,

it is handled by switches, depending upon how the

virtual circuit has been configured to accommodate

each subscriber's networking needs

Frame Relay devices The common devices that

com-prise a Frame Relay network include computers,

ter-minals, and circuit-related equipment They generally

fall into two categories, data terminal equipment

(DTE) and data circuit-terminating equipment (DCE)

The DTEs (desktop computers, terminals, routers,

etc.) are usually located on the subscriber's premises,

while the DCEs (the various circuit-connecting and

-switching devices) may be locally installed or may

be managed by the Frame Relay service provider

Frame Relay extensions A consortium of vendors

seeking to enhance the basic capabilities of Frame

Relay in order to meet the demands of the

commer-cial marketplace extended the Frame Relay protocol

with a Local Management Interface (LMI)

specifi-cation in 1990 Organizations such as CCITT (now

lTU-T) andANSI developed versions ofthe LM! that

are now generally adopted

The LM! is a specification for information exchange

between devices that is enhanced with capabilities

such as global addressing, multicasting, and

addi-tional status messages Theframe-relay lmi-type

in-terface configuration command provides a means to

select the type of LMI interface, and theFrame

Re-lay keepalive command enables LMI for serial lines.

LMI statistics can be displayed with the showframe-relay lmi EXEC command.

Frame Relay flow control Flow control, the man-agement ofmovement offrames within and between networks, is not explicitly defined in the Frame Re-lay specification, and thelTVhas defined general concepts and standards for handling flow and con-gestion In practice, congestion can be prevented in Frame Relay networks by establishing committed in-formation rates (CIRs) to each user, denying the con-nection ifinsufficient bandwidth is available, and by discarding frames above the CIR Existing conges-tion can be signaled to the user in the form of back-ward explicit congestion notification (BEeN) and forward explicit congestion notification (FECN) Frame Relay Forum FRF.Aninternational profes-sional association ofcorporations, vendors, carriers, and consultants promoting the Frame Relay network-ing technology, and supplynetwork-ing commercial Frame Relay products and services, established in 1991 The Forum develops and promotes specifications to sup-port the viability of Frame Relay and sponsors inter-operability events for designers, manufacturers, and vendors to test their Frame Relay-based equipment http://www.frforum.com/

Frame Relay Forum Implementation Agreements

IA A series of formal, approved agreements (stan-dards) developed and/or supported by the Frame Relay Forum The preceding chart gives a briefsum-mary of lAs, organized somewhat functionally The documents may be freely downloaded from the Net See Frame Relay Forum chart

Frame Relay frame format The format for a frame

is based on Link Access Protocol D (LAP-D) for ISDN Frames are also known as protocol data units Frame Relay Frame Format

012345678901234567890123456789012345678901234567890123456789012345678901234567890

+ -/ -/ -+

I flag I address I information I FCS I flag I

+ -/ -/ -+

1 octet 2 to 4 octets variable 2 octets 1 octet

Header Structure

+ -+

+ -+

+ -+

DLeI data link connection identifier

C/R command/response

FECN forward explicit congestion notification

BEeN backward explicit congestion notification

DE discard eligibility

FUN! Flags are used to indicate the beginning and

end of a frame, which may be variable in length

The format specified for a frame includes a I-byte

(8-bit) flag, followed by 2 to 4 header address bytes,

followed by a variable number of information bytes,

followed by a 2-byte CRC code (frame check

se-quence), followed by a I-byte flag There are a

num-ber ofpossible configurations of the address field; it

may be two, three, or four bytes in length, as

deter-mined by the extended address (E/A) bit

Informa-tion for the Local Management Interface

enhance-ments is stored (e.g., DLCI information) in the frame

header

Frame Relay installationFrame relay

communica-tions connection services are generally available for

a monthly subscriber fee or per-data rate from a

lo-cal commercial provider, depending upon the speed

oftransmission One-time connect charges for

instal-lation and port configuration are common

Transmis-sion speeds up to 56-64 Kbps are typical, although

most vendors offer higher speeds for more money

In-house installations of Frame Relay networks are

also available

Frame Relay physical layer interfaceThe

specifi-cation for Frame Relay does not stipulate particular

physical connectors or cables In practice, however,

unshielded twisted pair (UTP) is commonly used in

ISDN implementations of Frame Relay

Frame Relay serviceFrame relay network service

consists ofa combination ofhardware, software, and

transmission services It provides multiple

indepen-dent multiplexed data links to another destination or

to several destinations through a process which is at

least as transparent as a leased line and less

expen-sive See Frame Relay installation

Frame Relay, voice overVoFR Frame relay

tech-nology provides an opportunity to combine data and

voice communications services over the same

net-work Analysis of typical voice communications

in-dicates that much of it is unnecessary (background

sounds, pauses, etc.) and can be screened out before

transmission over data networks This aspect offers

possibilities for processing and compression to

pro-vide for efficient transfer of digitally encoded voice

conversations Initially, there was no uniform

stan-dard for carrying voice over Frame Relay and

vari-ous schemes for its implementation had been

devel-oped In July 2001, the Frame Relay Forum

an-nounced FRF.20, an IP Header Compression

Imple-mentation Agreement that defines packet

encapsu-lation and compression negotiation to facilitate the

transmission of voice over IP

Frame Relay-capable interface deviceFRCID A

peripheral device that performs frame encapsulation

within a Frame Relay See bridge, encapsulation,

router

Frame Relay Implementors ForumAn association

of vendors supporting standards of interoperability

for Frame Relay implementations Acommon

speci-fication was first introduced in 1990 based on the

standard proposed by the American National

Stan-Frame Relay Forum Implementation Agreements

Number Date Description

FRF.6 Mar 1994 Service Customer

Net-work Management Imple-mentation

FRF.19 Mar 2001 Operations,

Adminis-tration and Maintenance Implementation

FRF.17 Jan 2000 Privacy

Implementa-tion FRF.12 Dec 1997 Fragmentation

Imple-mentation FRF.13 Aug 1998 Service Level

Defini-tions Implementation FRF.l4 Dec 1998 Physical Layer

inter-face Implementation FRF.l.2 Apr 2000 User-to-Network

(UNI) Implementation FRF.4.1 Jan 2000 User-to-Network

In-terface (UNI) Implementa-tion

FRF.2.1 July 1995 Network-to-Network

Interface (NNI) Implementa-tion

FRF.lO.l Sept 1996 Network-to-Network

SVC Implementation FRF.18 Apr 2000 Network-to-Network

FR/ATM SVC Service Inter-working Implementation FRF.5 Dec 1994 Frame Relay/ATM

Network Interworking Implementation

FRF.8.1 Feb 2000 Frame Relay/ATM

PVC Service Interworking Implementation

FRF.7 Oct 1994 PVC Multicast Service

and Protocol Description FRF.l5 Aug 1999 End-to-End Multilink

Implementation FRF.16 Aug 1999 Multilink UNI/NNI

Implementation FRF.3.2 Apr 2000 Multiprotocol

Encap-sulation Implementation FRF.9 Jan 1996 Data Compression

Over Frame Relay Imple-mentation

FRF.l1.1 May 1997 Voice over Frame

Re-lay Implementation FRF.20 Jun 2001 IP Header

Compres-sion Implementation

frame storeA high-capacity digital video storage buffer Frame stores are most commonly used in two categories of applications: (I) those that require im-age buffering to provide sufficient speed for continuous

Fiber Optics Illustrated Dictionary

display (see frames per second), such as computer

editing or display systems, and (2) those that require

image bufferinginorder to create complex,

compos-ite, or multiple display systems (such as video walls)

Inthe first instance, the device from which the frames

are being displayed or the display software may not

be fast enough to read and display at 30 or so fps By

using a frame store, sufficient frames can be buffered

infast access memory (or on a very fast drive) to

pro-vide quick display and the illusion of continuous

motion If the display software creates unwanted

ef-fects on the screen when loading the next frame, the

transition can sometimes be smoothed with

double-buffering or grabbing the next frame from the frame

store rather than from a hard drive.Inother words,

the new image is preconstructed in memory while the

current image is being displayed, and the buffered

image can then be displayed instantly over the

pre-vious frame, rather than reading in and

decompress-ing the frame and then displaydecompress-ing it line by line over

the previous frame

In the second type of application, a frame store can

help compose a complex image, such as computer

graphic effects for a movie, which may have been

raytraced one frame at a time, but which, when

com-bined with footage of the actors, needs to match the

speed ofthe action Aframe store can also be used as

a component of a video wall, say 20 monitors in a

four by five grid, which shows 1/20thof the actual

image on each monitor Since this display takes some

computing power to split up an image into 20

sepa-rate subimages, the image grid could be segmented

and prestored, so all the monitors display the correct

parts of the grid at the same time See buffer, frame

buffer, desktop video

Frame Switching bearer service FSBS In a sense,

an enhanced version ofFRBS, in that it includes the

basic functions of FRBS, plus frame

acknowledg-ments and other error and flow control services It is

more similar to X.25, from which Frame Relay was

derived, than the basic, streamlined FRBS service and

reintroduces some of the features ofX.25

frames per second Aphrase describing display speed

for TV broadcasts, video, and film animations The

two most important aspects that determine this speed

are human perception and display technology

Through persistence of vision and expectation,

hu-mans perceive still frames displayed quickly one

af-ter the other as motion It requires only about 15 to

30 frames per second (depending upon the amount

of detail and speed of the action) for these images to

appear to be continuous motion Most animations are

created with 24 to 30 frames per second Since

mo-tion media can be displayed only at the fastest speed

of the display medium (usually a cathode-ray tube),

the technology also determines the display rate, with

speeds of 15 to 60 fps being implemented, and about

20 to 30 fps most often used See frame; frame rate,

video; refresh

framing bit FB A noninformational bit that can be

used for a variety ofsignals in frame-based networks

A framing bit can signal the frame beginning or end

and error conditions, and it can be used for synchro-nization, depending upon the quantity and pattern of frames.Inits simplest implementation, the framing bit signals to the receiving equipment that a new frame is about to begin

In North America, Superframe and Extended Super-frame standards are used for implementing Tl net-work services Each frame in a T1basic Superframe (SF) includes eight information bits and one fram-ing bit.InSF, there are two types offraming bits: ter-minal framing (Ft) and signaling framing (Fs) bits

In Extended Superframe (ESF), there are three types

of framing bits: frame pattern sync (Fps), datalink (DL), and cyclic redundancy check (CRC-6) The datalink framing bits differ somewhat, depending upon whether ESF is implemented according to ANSI

or AT&T standards The ANSI format provides for the transmission of a Performance Report Message (PRM) that allows actual performance to be com-pared with established thresholds and an alert to be generated if anomalous conditions are detected By evaluating the pattern of framing bits in a series of frames, synchronization can be established.In for-mats such as DS-l C, a framing bit can be stuffed to generate 26-bit information units allowing for syn-chronization and framing

franchise A government granted right to offer com-munity public right-of-way for exclusive commercial communications services, such as phone services or cable broadcast services The franchise fees, or a por-tion ofthem, may be used by local government agen-cies, a portion ofwhich may be allocated to local Des-ignated Access Providers (DAPs) for facilities fund-ing Some of the earliest local phone companies may

be partially exempt if they gained their exclusivity prior to regulation (grandfathering)

Franklin, Benjamin (1706-1790) An American businessman (printer), statesman, scientist, and phi-losopher who did numerous experiments in electric-ity and printing He shared his discoveries openly and coined many of the terms now used to describe me-chanics and electricity He called vitreous

electric-ity, demonstrated by rubbing glass with silk,positive

electricity, and resinous electricity, demonstrated by

rubbing amber with wool, negative electricity He did

experiments with lightning and stored electrical charges in a device called a Leyden jar, and he es-tablished that man-made electricity and atmospheric electricity had the same properties These experi-ments were enthusiastically received and replicated throughout Europe, spurring much interest and de-velopment in the field of electricity

Ben Franklin also developed some early document duplication techniques which he used on his own printing press to help him manage his voluminous records and correspondence

Ben Franklin was a successful business owner at a relatively young age and always hoped to retire early

to devote the rest of his life to scientific inquiry and his various hobbies, but the American Revolution and the overwhelming public demand for his diplomatic skills kept him occupied for long hours right up to

Leyden jar.

Franklin InstituteA significant organizer and

pro-moter ofactivities related to general science, electrical

education, professional development, and

technologi-cal deveiopment in electronics The Institute

orga-nized many key American and international

exhibi-tions starting in the 1800s and is still well known for

its educational activities and awards for excellence

The Institute was founded by Merrick and Keating

in 1824 as The Franklin Institute ofthe State

ofPenn-sylvania for the Promotion of the Mechanic Arts in

honor of scientist and statesman Benjamin Franklin

Since 1926, the Institute has been publishing the

Journal of the Franklin Institute. In 1933 it began

construction of the Fels Planetarium and has

admin-istrated the Franklin Institute Science Museum since

1934 In the 1990s, multimedia theaters were added

to provide enhanced educational presentation

capa-bilities See Benjamin Franklin Institute (not

affili-ated) http://www.fi.eduJ

fraudn.Deceit, trickery; unauthorized access or use,

especially under an assumed identify, such as a false

username, or through the use ofunauthorized

equip-ment; misrepresentation of identity, products or

ser-vices, especially for monetary gain

Unfortunately, fraud is now rampant on the Internet

A criminal with fraudulent intent can contact millions

ofpotential victimsinseconds at minimal cost

There are many different types offraud on computer

networks Fraudulent vendors use names that sound

or look like recognized businesses and create

copy-cat Web sites selling substandard products (or no

products at all) They use email with embedded Web

page links to fool people into thinking they are

veri-fying their passwords on financial sites when in fact

a Trojan horse program is capturing their passwords

or credit card numbers Fraudsters also use fictitious

email addresses, anonymous emailers, and elaborate

mail routing to obscure their locations and identities

Naive users, especially teenagers, children, senior

citizens, or adults from small communities, are

be-ing defrauded on a massive scale by Internet-based

get rich/pyramid/multilevel marketing schemes, fake

contests, promises of off-shore commission profits,

black and gray market pharmaceuticals, videos, and

CDs, identity and credit card number theft, and

so-licitations to patronize illegal pornographic sites

Un-solicited bulk email (spam) is one of the primary

ve-hicles used by fraudulent companies to contact and

negotiate with large numbers of potential victims to

perpetrate these crimes

Many of these schemes are so sophisticated that it

may be difficult, even for a computer professional,

to recognize the deceit Many existing laws should

be sufficient to protect victims from Internet fraud,

but existing black market, theft, piracy,

embezzle-ment, pornography, and false advertising laws (which

cover the majority ofInternet-related crime) are

dif-ficult to enforce unless resources for law enforcement

and consumer education are increased

http://wwwl.ifccfbi.gov/

field from which the energy flow proceeds as though emanating from a point source near the antenna, also called far-field region.Itis considered to be one of three basic regions without distinct transition bound-aries that are identified as you move away from an antenna source The Fraunhofer region is the one far-thest from the source beginning at a point where the angular field distribution is considered to be indepen-dent of the distance from the antenna See Fresnel region

Fraunhofer spectrumThe portion ofthe solar spec-trum visible to humans, i.e., the portion where the spectral absorption lines can be clearly seen The dark lines have come to be known as Fraunhofer lines Fraunhofer observed that the range of spectral lines varied depending upon which celestial body was the source ofthe light This information was valuable in that it led to observations about light emanating from stars with different chemical compositions, allowing scientists to analyze the composition ofbodies in our universe from a distance The Fraunhofer spectrum can be taken as a baseline reference against which spec-tral shifts can be compared See Wallaston, William

Fraunhofer, Joseph von (1787-1826) A German physicist who was skilled at applied optics and lens design As a scientist, he applied his knowledge to the study of the Sun, its spectra, and the diffraction

of light He systematically set about measuring the position of hundreds of solar spectral lines and clas-sified the most prominent lines He then developed a diffraction grating and a general grating equation for measuring the wavelengths of colors and of lines in the dark spectrum Various aspects ofspectral nomen-clature are named after Fraunhofer

FRBSFrame Relaying bearer service See Frame Relay

Free Software FoundationFSF A Massachusetts-based association committed to the development, ac-ceptance, and promotion ofopen, free software stan-dards and applications to benefit the world at large The freedom to copy and distribute software, and the freedom to modify, enhance, and improve software are encouraged by the FSF Thus, the programming and user communities benefit by the availability of constantly improving software and standards, and programmers have a broad, ready base of software from which to learn and to improve their skills The FSF has developed the integrated GNU software system, which includes assemblers, compilers, and more Donations to the FSF are tax deductible http://www.fsf.org/

free-space opticsFSO Aterm for optical transmis-sion technologies that do not require a physical waveguide such as a fiber optic cable.Aninfrared remote television control is an example of a free-space transmission device that projects data through line-of-sight "free space." Free-space optics is pro-moted as a means ofcompleting "the last mile" which

is the distance from major optical backbone transmis-sion services that separates most homes and busi-nesses in the U.S from established light-based