Fiber Optics Illustrated Dictionary - Part 51 ppsx

Fiber
Optics
Illustrated
Dictionary
provide
a
forum
for
participation
in
the
planning
and
administration
of
the General Services Admin-
istration's
long-distance
telecommunications
services
provided
through
the
FTS2000
program.
Since
then,
it
has
become
a

focal
point
for
the
development
and
administration
of
federal
technology
programs.
interapplication communications
lAC.
A
transpar-
ent
means
of
intercommunication
between
computer
software
applications
(e.g.,
between
a
word
proces-
sor
and

drawing
program).
A similar
concept
was
dubbed
Compound
Data Architecture
(CDA)
by
Digital
Equipment
Corporation
(DEC).
The
concept
is
now
frequently
implemented
in
layered
architec-
tures
on
multitasking
systems,
but
in
the

early
1990s,
surprisingly,
it
was
not
prevalent
on
desktop
systems.
Once
a user
has
experienced
the
ease
of
moving
around
data
and
images
among
different
types
of
ap-
plications
or
among

applications
from
different
ven-
dors,
it's
hard
to
go
back.
INTERBUS
An
open
systems
frame-based,
data
bus
interface
device
standard
and
protocol
for
high-per-
formance,
distributed
networks
for
manufacturing
and

process
control.
INTERBUS
standards
enable
devices
from
different
manufacturers
to
exchange
information
through
standardized
profiles
for
robotic
controllers,
peripheral
drives,
data
encoders,
indus-
trial
valves,
etc.
It
is
a
bit-oriented,

synchronous
pro-
tocol that
is
used with sensors and actuators.
INTERBUS
is
implemented
on
ring-based,
token-
passing
networks
and
utilizes
a
single
multipair
cable
to
interconnect
all
devices,
regardless
of
type
or
level
of
complexity.

See
actuator,
PROFffiUS.
IntercarrierInterface
ICI.
One
of
the
two
interface
ports
ofXA-SMDS
systems
which
is
used
to
specify
how
the
carrier
switch
sends
and
receives
data
from
an
Interexchange
Carrier's (IXC's)

SMDS
network.
The
other
interface
is
the
Subscriber
Network
Inter-
face
(SNI).
See
Exchange
Access
SMDS.
Intercast
An
Intel
term
for
technology
that
allows
a
consumer
to
interface
the
TV

set
with
a
computer
hooked
up
to
the
Internet,
to
receive
"push
technol-
ogy"
Webcasts
or
Netcasts,
that
is,
digital
broadcasts
of
information
and
entertainment
transmitted
over
the
Web
rather

than
through
television broadcast
air-
waves
or
television
cable
services.
The
digital
infor-
mation
from
the
Web
is
displayed
in
the
blanking
spaces
of
the
TV
signals,
so
the
TV
can

still
receive
normal
TV
broadcasts
in
addition
to
displaying
Intercasts.
See
Webcast.
Intercept
Service A service
in
which a call
to
a
changed
or
disconnected
number
is
routed
to
a
record-
ing
or,
ifa

recording
is
not
available,
to
an
Intercept
operator.
In
the
case
of
the
latter,
the
caller
will
be
verbally
asked
for
the
destination
number
and
the
operator
will
attempt
to

complete
the
call.
Interchange A
commercial
Internet
connection
ser-
vice
from
Ziff-Davis,
similar
to
some
of
the
other
large
Internet
Service
provisions,
but
with
a
slightly
more
technological
slant.
Interchange
Carrier

IC.
A
common
telecommuni-
cations
carrier
that
provides
inter-
or
intra-LATA
ser-
vices
through
local
public
exchanges
according
to
492
definitions
and
regulatory
guidelines
established
by
the
Federal
Communications
Commission

(FCC)
and
the
Telecommunications
Act.
See
Inter
Exchange
Carrier.
Interchange Format
See
Rich
Text
Format.
intercom
abbrev. intercommunication, inter-
communicator.
A
set
of
at
least
two
devices,
mini-
mally
atransmitter
(with
a
microphone)

and
receiver
(with
a
speaker)
or
two
transceivers,
over
which
re-
mote
communication
can
take
place
in
at
least
one
direction.
Most
intercoms
are
audio
only,
but
audio/
visual
intercoms

are
becoming
more
prevalent
as
the
technology
becomes
more
readily
available.
Intercoms
can
generally
be
categorized
as
wired
or
wireless.
Wired
intercoms
sometimes
use
existing
wiring
(e.g.,
doorbell
wires
in

the
walls
of
houses).
Wireless
intercoms
use
broadcast
frequencies
sent
through
the
air
or
sometimes
through
building
wir-
ing
using
the
AC
sockets
as
an
interface
to
the
wir-
ing

for
better
transmission.
Many
wired
and
wireless
intercom
speakers
are
wall
mounted,
like
the
PAsystems
in
schools
or
hospitals,
and
the
transmitter
may
be
attached
to
a
handheld
mi-
crophone

or
operated
through
a
telephone
handset.
Baby
monitors
are
a
type
of
wireless
mobile
inter-
com,
in
which
one
unit
is
placed
near
the
baby
and
the
other
is
placed

near
the
parents
or
babysitter
or
attached
to
their
clothing
so
they
can
move
around.
Intercoms
are
often
incorporated
into
phone
systems,
so
that
the
handset
or
speakerphone
is
the

transmit-
ter
and
the
receiver
is
a
speakerphone
on
another
con-
sole
(or
on
several
consoles
in
broadcast
mode).
The
distinction
between
wireless
intercoms
and
wire-
less
radios
is
not

a
hard
and
fast
one;
there
is
overlap
in
capabilities
between
sophisticated
intercoms
and
simple
radio
systems;
the
main
difference
is
in
ease
of
use.
Intercoms
and
basic
two-way
short-distance

radios
tend
to
be
unlicensed push-button devices,
whereas
wireless
radios
tend
to
be
licensed
devices,
some
requiring
a
higher
level
of
expertise
to
operate.
In
this
sense,
a
computer
videoconferencing
system
can

be
called
an
intercom
system.
Once
the
software
application
is
installed
and
launched,
the
u~er
need
only
sit
in
front
ofa
microphone
and
small
camera
in
order
to
communicate
with

the
person
at
the
other
end
of
the
connection.
No
sophisticated
skills
are
needed
and
even
the
push-button
aspect
of
the
com-
munication
has
been
eliminated.
Since
videoconferencing
systems
aren't

subject
to
the
same
distance
restrictions
as
low-power
wireless
de-
vices,
it's
possible
that
small
flat-screen
monitors
with
built-in
speakers
will
eventually
replace
traditional
intercoms.
Parents
will
be
able
to

readily
see
what
their
kids
are
doing
in
daycare
or
at
school.
Friends
can
keep
in
touch
without
making
long-distance
calls.
Business
associates
can
discuss
important
projects
or
interact
in

meetings
from
home
or
a
remote
office
(or
from
the
road
with
a
wireless
modem).
When
high-
speed
communications
become
available
to
a
major-
ity
of
users,
Internet
intercoms
may

well
become
one
of
the
most
prevalent
telecommunications
technolo-
gies.
See
public
address
system,
videoconferencing.
© 2003 by CRC Press LLC
Interdepartment Radio Advisory Council
IRAC.
An
assemblage
ofcommittees, subcommittees,
and
working
groups
providing expertise
and
notification
to
the
International

Telecommunication
Union
(ITU)
regarding
the
allocation
and
management of
radio
frequency
spectra.
IRAC
develops
procedures,
pro-
cesses
requests,
and
assists
in
assigning
frequencies
to
U.S.
Government
radio
stations.
IRAC
includes
the

Frequency
Assignment
Subcommittee
(PAS),
the
Spectrum
Planning
Subcommittee
(SPS),
the
Tech-
nical Subcommittee (TSC),
the
Radio
Conference
Subcommittee
(RCS),
and
the
International Notifi-
cation
Group.
Interexchange
Carrier
Compatibility
Forum
ICCF.
An
organization
that

developed
an
expansion
plan for telephony Carrier Identification Codes
(CICs)
when
they
became
scarce
in
the
late
1980s.
The
ICCF
also
served
as
a liaison
in
standardization
efforts
for
fiber
interconnectivity
in
the
mid-1980s.
interface
n.

A
hardware
connection,
or
logical
con-
nection
or
translation point
between
two
or
more
de-
vices
or
transmissions
media.
Interfaces
are
an
intrin-
sic
part
of
interconnected
computers,
peripherals,
and
networks.

Almost
every
aspect of
data
and
electrical
connections
in
the
telecommunications industry
uses
a different
format
or
version
of
a
format,
and
the
in-
terface
is
the
point
at
which
all
these
different

hard-
ware
and
software
junctions
come
together.
Common
electronic
interfaces
include
docking
bays,
cradles,
cable
connectors,
peripheral
card
connectors,
card
slots,
and
chip
sockets.
interface, human-machine
n.
The
point ofcontact
or
translation

between
humans
and
machines.
• A
hardware
interface
is
a
device
or
system
that
translates
human
movement,
speech,
or
sensory
output
into
impulses
(usually electromagnetic
or
mechanical,
though
chemical interfaces
also
ex-
ist)

that
the
machine
or computer
device
can
in-
terpret
and
compute
into
data
and
instructions
or,
conversely,
that translates
machine
signals
into
sensory
output
or
information meaningful
to
hu-
mans.
Human-machine
interfaces
come

in
many
vari-
eties, including digital, analog, mechanical,
chemical,
or
a mixture
of
these. Examples of
hardware
input
interfaces
include
microphones,
keyboards,
joysticks, temperature sensors, serial
connectors,
video
cams,
data
gloves,
and
pressure
pads.
Hardware
output interfaces include
moni-
tors,
speakers,
pulsing lights, thermostat control-

lers,
infrared
device
controllers,
and
more.
• A software interface
is
a
system
ofalgorithmic
procedures/functions
to
meaningfully
communi-
cate
information
and
options
to
humans
and/or
to
interpret
human
communication
and
sensory
into
machine

instructions.
Common
software
interface conventions include
the
use
of
textual
queries
and
responses,
graphi-
cal
pointers,
folders,
menus,
and
other culturally
meaningful
icons
that
indicate
the
state of
the
de-
vice,
availability of services, current point
in
a

process,
etc.
Human-machine interfaces
evolve
through
a
system
oftrial-and-error
combined
with
the
sometimes
id-
iosyncratic preferences of
the
people
who
design
the
applications
or
market
the
devices
to
the
general
pub-
lic.
At

the
present
time,
software interfaces
are
often
developed
intuitively
by
computer
programmers
with
little
or
no
input
from
users
even
though
they
are
in-
tended
to
satisfy
the
needs
ofa
broad

spectrum
of
people, rather
than
the
more
individual
needs
and
preferences of
the
programmer,
in
order
to
produce
products
with
commercial viability.
Unfortunately, interfaces
become
entrenched
even
if
they
are
no
longer appropriate
or
practical.

Early
ver-
sions
ofatechnology
are
often
designed
to
overcome
pioneering
design
limitations.
As
the
limitations
are
overcome,
the
increasingly inefficient
interface
may
be
retained because
users
have
become
accustomed
to
it
or

because
it
is
expensive
to
change
production
lines.
The
QWERTY
typewriter
keyboard
layout
is
a
good
example.
It
was
designed
for
historic
manual
typewriters
and
laid
out
with
the
letters organized

so
they
would
slow
down
the
typist
to
help
prevent
jam-
ming
that
occurred
with
old-style
mechanical
keys.
When
electric typewriters
and
computer
keyboards
were
developed without
the
jamming
problems,
the
QWERTY

layout
was
retained
even
though
the
origi-
nal
reason
for
the
layout became irrelevant.
The
concept of
the
interface
is
an
important
one
as
it
influences
how
comfortably
and
efficiently
humans
can
utilize a

technology.
Ease
of
use
and
interface
design
are
essential
to
the
success
and
proliferation
of
many
telecommunications products. Interface
de-
sign
also
reveals priorities; sometimes
humans
are
expected
to
adapt
to
the
limitations ofa technology
rather

than
the
technology being
designed
to
serve
the
needs
of
humans.
Interface Control Application Programming In-
terface
ICAPI.
A telecommunications
call
control
library
that
facilitates
network
interface
access
for
T1
robbed-bit signaling
systems
or
TIlE1
CAS.
It

fits
between
the
operating
device
drivers
and
the
appli-
cation.
There
are
similar
call
libraries
for
ISDN
and
ANAPI.
An
ICAPI
protocol
uses
bit transitions
and
in-band signaling
to
establish calls
and
transmit

call
information. Events and channel states may be
logged.
Interface Data Unit
IOU.
In
ATM
networking,
in-
terface control information transferred
to
and
from
the
upper layer
in
one
interaction
across
the
layer.
A
service
data
unit
(SOU)
may
be
passed
across

ATM
Adaptation Layer 5
(AAL5)
as
an
IOU
correspond-
ing
to
one
protocol
data
unit
(DPDU)
in
a
one-to-one
correspondence
or,
depending
upon
the
type
ofser-
vice
(e.g.,
message
or
streaming
mode),

the
SDU
may
also
be
passed
across
AAL5
in
more
than
one
IDU.
Interface Device In Frame
Relay
networks,
the
In-
terface
Device
provides a
link
between
an
end
device
and
the
network through encapsulation.
See

encap-
sulation,
Frame
Relay Capable Interface
Device.
interference Extraneous, unwanted signals that
hinder transmission or perception of
the
desired
sig-
nal.
Types
ofinterference include
noise,
static,
pops,
493
© 2003 by CRC Press LLC
Fiber
Optics
Illustrated
Dictionary
crackles, echo, babble, chatter, crosstalk, cosmic
noise, and background noise. See individual entries
in
this dictionary
for
details.
interference grating A grating created through a
photoresist laser etching process

by
exploiting
the
in-
teraction between the intersection
of
collimated light
beams
of
the
same wavelength. It
is
sometimes called
a holographic grating due
to
the three-dimensional
tapered effect between high and
low
points
in
the
grat-
ing. The sinusoidal cross-section makes
it
difficult
to
impose a blazed pattern on
an
interference grating,
putting some limits

on
the efficiency
of
this type. In-
terference gratings came into practical use
in
the late
1960s. They are favored over ruled gratings for a
number
of
precision applications due
to
greatly re-
duced incidence
of
stray light, particularly
in
grat-
ings with fine grating periods (reduced distance
between adjacent facets). Photographically etched
Interferometer Examples
Type Abbreviation Description
Fabry-Perot
FPI
Fizeau
FI
Mach-Zehnder
MZI
494
A high-resolution interferometer utilizing multiple reflections

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

cooperation
with
the
University ofPittsburgh,
MIT
uses
this
type
of
interferometer
with
a cooled gallium-arsenide photocathode photomultiplier
as
a
detector,
with
a computer
as
a controller,
for
night
sky
observations. There
are
FPIs installed
in
the
Antarctic,
Norway,
and

many
other locations
to
remotely
sense upper atmosphere
wind
and
temperature conditions. Doppler
concepts
are
incorporated
into
the
sensor
readings
for
meteorological observations.
Fabry-Perot
filters
have
also
been
suggested
by
Wickham
et
al.
for
use
as

sub-
band
tuning
mechanisms
(in
conjunction
with
Bragg reflection gratings)
for
optically channelizing
radio
frequency
(RF) signals
for
spectral analysis ofthe
very
high
frequencies
now
used
for
communications signals. Bragg reflection
gratings
and
FP
filters
have
further
been
described

by
Bao
et
al.
as
a mechanism
for
determining wavelengths oftransmitted
or
reflected light
through
a calibrated
wavelength reference,
thus
creating a reference
system.
A basic
type
of
image
plane interferometer useful
for
noncontact testing
of
surface characteristics
and
for
telescope design. The Fizeau interferometer
produces a direct
image

from
the
source
and
does
not
incorporate
the
same
degree
of
beam
diversion characteristics
as
the
other interferometers mentioned
here.
The
FI
is
used
in
many
astrophysical applications.
More
recent digital phase-
shifting
FIs
have
been

developed
by
CSIRO
for
in-house precision metrology of
optical components.
A historic interferometer
descended
from
the
Twyman-Green interferometer.
With
improvements,
the
MZI
is
still
common
as
a calibration
and
diagnostic
instrument.
It
is
most
often
used
in
aerodynamics, thermal

transfer,
and
plasma
physics,
but
is
also
being
studied
in
fiber
optics research.
The
MZI
is
favored
for
many
educational applications,
as
a basic
model
can
be
built
by
students
in
a rectangular
or

parallelogram configuration. Depending
upon
the
alignment of
the
reflecting surfaces, interference
fringes
mayor
may
not
be
produced
and,
by
controlling
the
length
of
the
optical path, phase shifts
can
be
introduced
in
a controlled
manner.
The
extent
of
the

shift provides a
means
to
monitor relative changes
in
the
optical
path,
thus
providing
useful
measurement
information.
The
beam
phasing characteristics of
an
MZI
can
also
be
modeled
in
computer software.
The
MZI
is
both
simple
and

sophisticated, depending
upon
how
it
is
implemented.
It
is
not
only
a
good
student project,
but
also
has
been
proposed
for
use
as
an
atomic
interferometer.
MZIs
are
useful
in
the
fabrication

and
testing ofcomponents
and
various sensors
used
in
telecommunications.
They
have
also
been
incorporated
into
integrated
circuits
for
converting optical wavelengths
and
have
been
developed
into
directional coupler switches.

cont.
© 2003 by CRC Press LLC
gratings are often easier
to
impose
on

nonplanar
shapes than machined ruled gratings.
On
the other
hand, they
also
tend
to
require higher intensity light
sources than ruled gratings.
By
placing photoresistive material
in
an
interfero-
meter
and
controlling the angle at which a light beam
hits and rebounds
from
a reflective surface, it
is
pos-
sible
to
have
a
single
light source
etch

astandingwave
interference pattern, with the angle related
to
the dis-
tance between grooves.
If
two planar beams
of
the
same
wavelength and intensity (at the point
of
inter-
section)
are
aimed
from
slightly different directions
onto a planar photoresistive surface, they will etch
out a regularly spaced, grooved
classical grating.
Other
types
ofwaves and other imaging surfaces
ex-
ist,
some
of
which are useful
for

compensating
for
the characteristics
of
other components, but the
abovementioned are common
in
the
fabrication
of
semiconductor gratings. See diffraction, grating,
interferometer, photoresist, ruled grating.
interference guard band See guard band.
interferometer Because
of
its wavelike properties,
a beam
of
coherent light can
be
split and realigned
in
such a
way
that factors that interfere with
one
of
the
beams
can

be
detected when compared
to
an
unim-
peded
reference
beam
or,
more
simply,
the
split beams
can
be
compared
to
detect subtle changes
to
one
or
more
of
the
beams. Thus, a device that detects and
displays interference between
two
or
more light wave
trains

and,
optionally, compares wavelengths against
reference displacements
is
called
an
interferometer.
Because light technologies can
be
very precise, com-
pared
to
mechanical devices, interferometers
can
be
used
for
very
fine
detection and calibration.
The
in-
terference pattern information derived
from
an
inter-
ferometer
is
useful
in

measurement or calibration,
for
example,
to
determine angular positions
in
satellite
tracking. A series
of
horizontal or vertical measure-
ments
at
precise distances along apath
can
yield data
that
can
be
processed
to
yieldplanar information
(e.g.,
a height profile
in
an
optical fiber).
There are avariety
of
types
of

interferometers, rang-
ing
in complexity
from
simple lab-built student
mod-
els
to
more sophisticated instruments that incorpo-
rate integrated circuit (IC) concepts. There are also
different modes
for
which
an
interferometer
can
be
designed.
The
optical path length
of
a test
and
refer-
ence beam can
be
changed
in
their relationship
in

a
series
of
phase shifts.
In
an
optical
fiber,
the
result
is
a lateral shift
in
the interferometric fringe pattern
to
measure the dimensions
of
a surface. Another
ap-
proach
is
to
scan
down
through a fiber
to
produce
an
interference signal along a series
of

points
on
a sur-
face. With digital processing, the data can be as-
sembled
to
generate a surface height profile.
Interferometers have been proposed
as
instruments
to
determine electrical states
in
silicon-based inte-
grated circuits (ICs)
and
as
diagnostic instruments
for
optical computer networks. One interesting applica-
tion is the light-in-flight speckle interferometer
Interferometer Examples, cont.
Type Abbreviation
Description
Michelson
MI
A
basic
interferometer
developed

by
A.A.
Michelson
to
conduct
the
Michelson-
Morley
experiment
in
the
1880s.
The
scientists
used
the
interferometer
to
determine
whether
a
theoretical
medium
called
the
aether existed
and
could
be
detected.

Michelson
received
a
Nobel
Prize
in
1907
for
his
discoveries in
optical
science.
In
a
Michelson
interferometer,
a
monochromatic
point
light
beam
is
split
in
two
by
a partially reflective
material,
such
that

one
beam
continues
in
the
original
direction,
and
the
other
is
reflected
(usually
90°)
from
the
original
course.
The
beams
are
recombined
with
the
resulting interference patterns displayed
on
a
screen.
These
are

derived
from
the
wavelike characteristics
of
light
and
can
be
analyzed
to
determine
vibrational
or
thermal
effects,
which
are
useful
in
fabrication
and
diagnostics.
The
image
in
a Michelson interferometer
is
not
viewed

directly
as
in
a Fizeau interferometer
but,
in
viewing
instruments
such
as
telescopes,
can
be
reconstructed.
By
calibrating
the
MI
with
a
known
reference,
the
wavelengths
ofother
unknown
materials
(e.g.,
gases
around

astronomical
bodies)
can
be
studied
through
known
interference characteristics.
MIs
are
also
used
to
develop
standards
in
atomic
lengths.
Twyman-Green
TGI
A
basic
type
of
interferometer
used
as
an
optical fabrication
and

diagnostic
tool,
developed
by
Frank
Twyman
and
Arthur
Green
in
the
early
1900s.
The
modem
TGI
is
based
upon
a
monochromatic
point light
source
at
the
focal
point ofa
lens.
By
revealing patterns of

optical
interference resulting
from
unequal
light
paths,
the
TG
I
can
be
used
to
assess
optical
surface
characteristics
such
as
the
flatness
of
a
surface,
performance ofa
component
(e.g., aprism),
or
deviation
from

a
reference
shape.
495
© 2003 by CRC Press LLC
Fiber
Optics
Illustrated
Dictionary
presented
by
Swedish
engineers
for
evaluating
3D
shapes
by
using
ultrashort laser
light
pulses.
On
a
software level, algorithms
for
phase-stepping
in-
terferometry
have

been developed
by
Chinese sci-
entists.
Interferometers
are
important
in
many
aspects
of
as-
tronomy.
Not
only
are
telescopes
based
upon
inter-
ferometric
principles,
but
Fizeau
interferometers
(FIs)
are
included
as
payloads

on
space
missions,
selected
for
their
accuracy
and
capability
of
sensing
over
a
wide
field
The
Global
Astrometric
Interferometer
for
Astrophysics
(GAIA)
mission,
for
example,
includes
three
stacked,
mechanically
connected

FIs
designed
to
observe
about
50
million
stars.
Historic
interferometers
were
based
upon
noncoher-
ent,
mixed-wavelength
light,
while
interferometers
developed
since
the
invention
of
lasers
typically
use
coherent,
nearly
monochromatic

light.
The
Interfer-
ometer
Examples
chart
includes
a
short
list
of
some
common,
representative
interferometers
used
in
re-
mote
sensing,
and
component
fabrication
and
testing
applications
relevant
to
telecommunications.
Interferometers

may
be
further
optimized
for
a
par-
ticular
task
such
as
assessing
the
cleave
(
terminal
cut)
of
an
optical
fiber
by
forming
an
interference
pattern
between
the
fiber
surface

and
an
optical
reference.
A
CCTV
camera
or
other
display
device
may
be
used
to
enlarge
and
display
the
cleave
so
the
angle
and
evenness
of
the
cut
can
be

seen.
A
divergence
of
angle
can
be
counted
as
a
specific
number
of
fringes
in
a
fiber
ofa
specified
diameter.
The
shape
of
the
fringe
pattern
can
indicate
the
evenness

of
the
surface.
The
inteferometer
may
be
customized
to
be
self-calibrat-
ing
for
this
task
and
accurate
within
a
tolerance
of
one
fringe,
enabling
a
cut
to
be
accepted
or

rejected
(and
possibly
recut),
before
connecting
to
other
com-
ponents.
Some
interferometers
can
interpret
the
vi-
sual
information
into
digital
data
for
further
process-
ing,
thus
enabling
lists
or
graphs

of
component
char-
acteristics
such
as
angle
of
cut,
smoothness,
radius
of
curvature,
etc.,
to
be
generated.
See
beam
splitter,
cleave,
coherent
light,
ferrule,
spectrometer.
interferogram A
visual
measurement
diagram
de-

rived
from.output
from
an
interferometer.
A
series
of
interferograms
may
be
digitally
processed
to
gener-
ate
a
surface
height
profile
of
the
medium
observed
(e.g.,
optical
fiber)
See
interferometer.
Interim Local Management Interface

ILMI.
A
means
of
providing
an
ATM
device
with
status
and
configuration
information
about
virtual
connections,
and
the
registered
ATM
prefixes,
addresses,
services,
and
capabilities available
at
its
ATM
Interfaces
through

the
Simple
Network
Management
Protocol
(SNMP)
and
an
ATM
Interface
Management
Infor-
mation
Base
(Mill).
ILMI
is
an
open
protocol
that
was
developed
as
an
interim
solution
by
the
ATM

Forum
in
the
mid-1990s
to
enable
the
exchange
of
UNI
management
information
through
direct
encap-
sulation
over
ATM
adaptation
layer
5
(AAL5).
How-
ever,
the
interim
designation
was
dropped.
ILMI

is
not
universally
implemented
and
meta-signaling
may
be
used
to
serve
this
purpose
on
some
systems.
496
Interim Number Portability
INP.
The
use
ofvari-
ous
telephone
subscriber
services,
such
as
call
for-

warding,
call
routing,
and
call
addressing,
to
allow
a
call
to
be
redirected
to
another
location,
usually
on
a
temporary
basis.
interior
In
ATM
networking,
an
item
such
as
a

link,
address,
or
node
inside
a
PNNI
routing
domain.
InteriorGateway Protocol
IGP.
A
family
of
network
routing
protocols
for
exchanging
information
with
other
routers
and
switches
on
the
same
system.
When

changes
occur
in
the
organization of
the
network,
these
changes
are
communicated
to
the
routers,
so
the
routing
table
databases
may
be
revised
accordingly.
InteriorGateway Routing Protocol
IGRP.
A
Cisco
Systems
proprietary
multipath

routing
protocol
de-
veloped
in
the
mid-1980s
for
routing
within
autono-
mous
systems.
Since
then,
the
protocol
has
been
fur-
ther
developed
and
many
users
have
replaced
Rout-
ing
Information

Protocol
(RIP)
with
IGRP
to
run
on
large,
heterogenous
networks,
like
the
Internet.
IGRP
was
intended
to
run
in
a
variety
of
network
environ-
ments
and
enhanced
IGRP
has
been

developed
to
sup-
port
TCP/IP,
IPX,
and
AppleTalk.
IGRP-enabled
routers
send
some
or
all
of
their
rout-
ing
tables
to
neighboring
routers
at
regular
intervals,
a
process
that
also
enables

distances
among
nodes
to
be
calculated
as
the
information propagates out
through
the
network.
interlace A
system
used
in
frame-based
video
image
display
to
display
images
in
two-frame
passes,
with
one
pass
imaging

the
odd
lines
and
the
next
the
even
lines
(or
vice-versa),
in
an
alternating
pattern.
Thus,
in
NTSC,
for
example,
an
interlaced
screen
is
imaged
in
two
fields
of262.5
lines

(to
make
up
the
full
525
scan
lines),
each
field
taking
1/60
ofa
second.
Some
flicker
can
be
seen
on
an
interlaced
display,
so
non-
interlaced
monitors,
including
multi
sync

monitors,
have
become
prevalent
on
computer
systems.
Gen-
erally,
the
faster
the
refresh,
the
more
stable
the
im-
age.
See
cathode-ray
tube,
field,
frame,
interleave,
multisync,
scan,
scanning
rate.
interleave

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

pro-
grams.
3.
In
networking,
to
transmit
pulses
through
a
single
path
through
time-division
from
more
than
one
source.
4.
In
graphics
file
storage
and
display,
a
means
of
arranging

the
image
data
so
that
all
odd
lines
of
the
image
and
all
even
lines
of
the
image
are
stored
or
displayed
as
a
group.
5.
In
magnetic
and
magneto-

optical
data
storage,
a
means
and
pattern
of
storing
information
on
a
disk
so
that
the
physical
character-
istics
of
the
read/write
sequence
are
accommodated
without
the
drive
head
needing

to
"backtrack"
to
find
the
next
section
of
data.
6.
In
multimedia
applications,
a
means
of
slicing
up
the
recording
space
so
that
dif-
ferent
media
(sound,
graphics,
etc.)
are

laid
down
in
strips
or
sections
on
the
tape
or
disc.
7.
A
data
trans-
mission error-correcting technique
in
which
code
symbols
are
arranged
in
an
interleaved
pattern
before
transmission
and
reassembled

upon
receipt.
© 2003 by CRC Press LLC
interleaved ,rideo A
video
display
in
which a
frame
is
constructed
and
displayed
by
alternately scanning
all
even
lines
and
then
all
odd
lines.
This
system
of
display
is
commonly
seen

on
televisions screens
and
on
some
NTSC-compatible computer screens. A
cer-
tain
amount
offlicker
is
usually noticeable
on
inter-
leaved
displays.
See
interlace.
interleaver
In
fiber
optics systems, a multiplexing
component
that
can
increase channel
density.
Filters
may
be

used
to
receive channels
or
route channel
groups.
See
add/drop
multiplexer.
intermediate frequency
IF.
In
heterodyne receivers,
the
beat
frequency
created
as
a result of
the
differ-
ence
between
a locally generated signal
and
the
in-
coming
radio
signal.

See
beat
frequency.
Intermediate Signaling NetworkIdentification
In
Signaling
System
7
(SS7),
acapability
that
allows
an
application process
in
the originating network
to
specify intermediate signaling networks for
noncircuit-associated signaling messages, and/or
to
notify
an
application process
in
the
destination net-
work
about
intermediate signaling networks.
intermittent

errors
Fault conditions that happen
occasionally,
sometimes
without apparent pattern,
or
occur
from
specific causes that
happen
seldom
or
ir-
regularly.
Difficult
to
anticipate
and
diagnose, inter-
mittent
problems
are
often
not
alleviated until a pro-
gram
has
been
run
hundreds of

times
or a computer
or
phone
network
has
negotiated thousands
of
calls.
intermodulation distortion A
type
of
audio
distor-
tion
that
occurs
when
multiple
tones
interfere with
one
another
in
a
way
that
is
not
harmonically related

to
the
original
tones.
internal modemAcomputer
modem
installed
inside
a larger
system
that
is
utilizing
the
modem.
Internal
modems
are
usually powered
by
the
system
in
which
they
are
housed
and
usually
take

the
form
of
small
PC
boards
or
very
small
PCMCIA
cards.
Sometimes
referred
to
tongue-in-cheek
as
"infernal
modems,"
in-
ternal
modems
can
be
finicky
to
install
in
systems
with
several

peripherals that require
IRQs.
Internal
modems
are
convenient
in
that they
are
out
ofsight
and
mind,
and
don't
take
up
extra
space
- a
real
plus
on
laptop
computers.
They
have
disadvan-
tages
as

well,
as
they
are
often machine-
or
platform-
specific
and
often
can't
be
reinstalled
in
a
new
com-
puter
of
a different
type,
as
can
most
external
mo-
dems.
External
modems
are

easier
to
swap
among
systems,
can
be
shared by a number
of
users
through
a switcher,
and
usually have status lights that are
handy
diagnostic
tools.
Since
most
internal
modems
install
in
a
slot
that
faces
the
back of
the

system,
they
often
don't
provide
status lights. In general, people
prefer internal
modems
on
small
mobile
devices
and
external
modems
on
desktop
systems
or
systems
with
shared
resources.
InternationalAd Hoc Committee
IAHC.
See
Inter-
net
International
Ad

Hoc
Committee.
International Alphabet
No.2
An
older alphabetic
coding
system
ofequal-duration pulses ofnegative
and
positive
volts
(called
marks
and
spaces)
in
groups
of
five,
to
represent character signals.
The
beginning
and
end
ofeach character
was
signaled
by

a start sig-
nal
and
a
stop
signal.
The
use
of
five
elements
in
two
possible polarities results
in
2
5
or
32
character
en-
codings.
Even
for
a basic alphabet,
this
was
some-
what
limited,

and
schemes
to
double
the
number
by
allowing a code
to
represent
one
of
two
characters
were
devised.
Something similar happened later with computer
character
codes.
International Alphabets
evolved
into
ASCII
and
became widely implemented
on
comput-
ers,
but there were
only

128
characters, insufficient
for
accents
or
math
symbols.
Many
developers
added
128
codes
for
a
total
of
256
characters
and
called
it
"extended ASCII." Technically, the extra codes
weren't standard ASCII and were not consistent
across
platforms. Another limitation
was
that they
couldn't
be
used

together,
the
user
had
to
select
ASCII
or
"extended ASCII" banks.
In
the
mid-1980s,
the
Amiga
and
Mac
removed
this
limitation, enabling
individual addressing
of
letters
in
both.
See
Appen-
dix
for
an
ASCII

chart.
See
ASCII,
Unicode.
InternationalAmateurRadio Union
lARD.
A
regu-
latory agency
and
proponent ofworld amateur radio
activity established
in
France
in
1925.
Amateur
ra-
dio
organizations throughout
the
world interact
with
a
high
degree
of
cooperation and communications.
The
IARU

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

dio
Relay
League.
/>International Atomic Time, Temps Atomique In-
ternational
TIA.
An
atomic
time
scale based
on
the
coordinated efforts of
more
than
200
atomic
clocks
from
more
than
50
centers
from
around
the
world,
which
are
maintained

in
France
by
the
Bureau
Inter-
national
des
Pods
et
Mesures.
Unlike
the
Coordinated
Universal
Time
(UTC),
which
is
adjusted occasion-
ally
in
leap seconds
to
maintain
some
coordination
with
the
Earth's

axis
rotation,
TIA
is
not
adjusted,
but
remains consistent
with
atomic
time
scales.
Other-
wise, TIA and
UTC
are very similar.
See
atomic
clock,
Coordinated Universal
Time.
International Business Machines
ffiM.
In
the
late
1800s, Herman Hollerith,
an
American engineer,
evolved

the
concept ofpunched
cards
as
a storage
medium
and
applied
it
to
the
development ofa
tabu-
lating machine,
an
early computer that
could
be
used
to
store
and
process information
in
categories.
This
resulted
in
Hollerith cards, Hollerith
code,

and
a
ma-
chine
which could tabulate
the
vast
amount
of
cen-
sus
data gathered
at
regular intervals
in
the
United
States. The tabulating machine dramatically im-
proved
the
efficiency
of
storing
and
analyzing cen-
sus
data,
and
Hollerith
formed

a company called
the
Tabulating
Machine
Company.
This
later
merged
with
several
other
companies
to
form
the
Computer-
Tabu-
lating-Recording
Company,
which sold a
wide
range
of
industrial products.
Thomas
1.
Watson,
Sr.
left
NCR

to
join
the
company
497
.
'
•
:
•
::
•
::
•.
:.':
.•
::
.•
:
)i:J(::
:
~j
© 2003 by CRC Press LLC
Fiber
Optics
Illustrated Dictionary
as
general
manager
in

1914,
and
remained
with
the
company
for
over
four
decades, eventually
passing
on
the
position
to
his
son,
Thomas
J.
Watson,
Jr.
On
Valentine's
Day,
in
1924,
the
name
of
the

company
changed
to
International Business
Machines
Corpo-
ration.
IBM
became
an
enormously
influential
com-
pany
in
the
business
and
computing market,
and
funded
or
partially
funded
the
research
and
develop-
ment
of

several
historic
room-sized
computing
ma-
chines.
IBM's research laboratory
has
contributed a
great
legacy
oforiginal
and
fundamental
scientific
discoveries of interest both inside
and
outside
the
computing industry.
IBM
inventions
are
awarded
more
than
1000
patents
per
year;

in
other
words,
IBM
develops
as
many
unique
inventions
in
a single year
as
the
best
individual
inventors of
the
1800s
devel-
oped
in
their
entire lifetimes.
In
1975,
IBM
released
its
first
microcomputer,

the
IBM
5100;
it
was
not
a
commercial
success,
and
it
was
not
until
5
years
later
that
the
first of
the
long
IBM
PC
line
was
introduced
to
the
public.

This
time
sales
were
good,
particularly
in
the
business
market,
and
IBM
and
IBM-licensed personal computer
tech-
nology
became
the
most
common
platform
for
desk-
top
computing.
See
Hollerith,
Herman;
IBM
Personal

Computer,
Jacquard
loom.
International Center for Technology Assessment
ICTA.
A
nonprofit,
bipartisan organization
dedicated
to
helping
government
officials
and
the
public
in
un-
derstanding technology
and
how
it
affects
human
society
and
the
environment.
ICTAexplores
and

com-
municates
the
social,
economic,
ethical,
political,
and
environmental
impacts
related
to
the
manufacture,
distribution,
and
application of technologies.
ICTA
also
uses
legal
petitions,
comments,
and
litigation
to
fight against harmful deployment
of
technology.
/>International Commission

on
Technology and
Ac-
cessibility
ICTA.
A
commission
to
explore
develop-
ments
in
technology
that
may
assist
people
with
dis-
abilities
and
to
promote
and
disseminate their
under-
standing
and
use.
ICTA

was
founded
in
the
1960s
in
Sweden
in
conjunction
with
Rehabilitation Interna-
tional
(RI)
and
the
Swedish
Handicapped Institute.
In
1969
ICTA
and
RI
developed
and
adopted
the
In-
ternational
Symbol
of

Access
(ISA).
/>International Commission for Optics
ICO.
An
in-
ternational
organization
affiliated
with
the
Interna-
tional
Union
of
Pure
and
Applied
Physics
the
sup-
ports
and
promotes
the
dissemination of
knowledge
in
optics,
founded

in
1947.
/>International Correspondence Chess Federation
ICCF.
This
is
one
of
the
more
interesting
historic
bod-
ies
using telecommunications
to
enhance gaming
communications.
The
ICCF
has
evolved
from
the
lnternationa/er Fernschachbund,
founded
in
1928,
which
was

succeeded
by
the
International
Correspon-
dence
Chess
Association,
in
1945,
to
become
the
ICCF
in
1951.
Correspondence chess hasn't only
been
conducted
through
postal
mail
services.
ICCF
members
and
chess
players
in
general

have
always
498
been
technology conscious
and
have
enjoyed
their
matches through
the
use
of
homing pigeons, tele-
grams,
trains, planes, computer
modems,
and
high-
speed
connections
to
the
Internet.
International Data Encryption Algorithm
IDEA.
A
European-designed,
128-bit,
single-key

encryption
algorithm
used
for
data
security.
It
has
been
incorpo-
rated
into
Pretty
Good
Privacy (pGP) partly because
it
doesn't
have
the
same
U.S.
export restrictions
as
other encryption algorithms.
Use
of
IDEA
is
license-
free

for
noncommercial
use.
See
encryption, Pretty
Good
Privacy.
International Development Markup Language
IDML.
An Internet protocol
and
associated set of
standards
to
facilitate development
in
a
global
con-
text.
In
1998,
the
Development Markup Language
(DML)
was
seen
as
a
means

to
support
the
markup
of information
on
computer networks
that
describe
developmental activities
and
mandatory data ele-
ments
described
by
relevant standards.
It
was
in-
tended
to
be
consistent
with
other
meta
data
schemes
and
capable

of
multilingual markup.
In
February
1999,
DML
was
renamed
IDML.
The
IDML
Work-
ing
Group
was
formed
to
develop
recommendations
and
a
process
for
electing
an
IDMLAdvisory
Group.
It
is
recommended

that
XML
be
used
for
Site
Descrip-
tion
files
even
though
other formats
may
be
used.
Extended
IDML
is
a superset of
the
Core
Activity
Schema
with
additional
audit
trail
and
informational
items.

IDML
was
established
as
a pilot standards-
track
candidate
in
early
200
I.
See
Extensible
Markup
Language,
IDML
Initiative.
International Electrotecbnical Commission
IEC.
An international standards-development
and
recom-
mending
body,
founded
in
1906
as
a result ofa
1904

resolution
at
the
Electrical
Congress.
The
IEC
pub-
lishes
standards
for
electrical, electronic,
magnetic,
and
related technologies
and
promotes cooperation
among
member countries.
IEC
standards
form
the
core
of
the
World
Trade
Organization's Agreement
on

Technical
Barriers
to
Trade
(TBT).
Hundreds
of
technical committees
and
working
groups
carry
out
the
mission
of
the
IEC.
Technical
committee papers
are
submitted
to
a full-member National Committee
members'
vote
in
preparation
for
approval

as
inter-
national
standards. />International Engineering Consortium lEe. A
nonprofit professional organization supporting
engi-
neering
research
and
education
sponsored
by
univer-
sities
and
engineering
societies,
founded
in
1944.
The
focus
of
the
organization
has
broadened
from
a
na-

tional
to
international purview
and
from
electronics
to
information engineering.
IEC
sponsors courses,
conferences, virtual exhibits,
and
a
number
ofpubli-
cations.
http://www.
iec.org/
International Federation for Information Process-
ing
IFIP.
A
nonprofit,
nongovernmental,
information
processing research organization.
IFIP
was
estab-
lished

in
1960
under
the
auspices of
UNESCO
after
the
first
World
Computer
Congress
of
1959.
A
num-
ber
of
technical
committees
provide
expertise
on
tech-
nological
matters.
/>© 2003 by CRC Press LLC
InternationalForum on the White
Paper
IFWP.

An
international
series
of
workshops,
founded
in
June
1998,
intended
to
bring
together professionals
and
experts
in
law
to
respond
to
White
Paper
recommen-
dations
for
assigned
numbers
on
the
Internet.

The
process
of
open
discussion
and
the
goal
of
self-
regulation
were
key
aspects
of
these
proceedings.
The
Internet
community
believed
that
it
was
possible
for
those
in
the
industry

to
produce
a
viable
system
for
assigning Internet addresses without government
takeover
of
the
process
and
used
the
Internet
itself
as
an
important
venue
for
meetings,
opinions,
and
some-
times
heated
debates
over
how

addresses
would
be
allocated
and
assigned.
As
a
result
of
initial
discussions,
a
California
non-
profit
public
benefit
corporation
called
the
Internet
Corporation
for
Assigned Names
and
Numbers
(ICANN)
was
tendered

as
a
draft
recommendation
as
a
means
to
coordinate
the
administration
of
Inter-
net
domain
names
and
Internet Protocol
(IP)
ad-
dresses.
The
draft
proposal,
jointly
presented
by
Net-
work
Solutions,

Inc.
and
the
Internet
Assigned
Num-
bers
Authority
(lANA),
was
discussed
in
September
1998
by
IFWP
with
regard
to
how
it
fell
within
a
model
of
common
principles
and
structure

specified
by
the
u.s.
Department
of
Commerce
Statement
of
Policy
on
the
Management
of
Internet
Names
and
Addresses.
Three
proposals
were
presented
to
the
Deptartment
of
Commerce
in
October
1998

by
dif-
ferent
groups,
and
testimony
was
presented
on
trans-
ferring
the
Domain
Name
System
to
the
private
sec-
tor.
ICANN's
bylaws
and
its
first
public
meeting
were
held
in

November
1998.
See
Intemet
Assigned
Num-
bers
Authority,
Internet Corporation
for
Assigned
Names
and
Numbers,
InterNIC.
International FrequencyRegulation Board
IFRB.
An
agency
established
by
the
International
Telegraph
Union
in
1868
to
manage
the

broadcast
frequency
spectrum.
In
1912,
the
IFRB's
Table
of
Frequency
Al-
locations
became
mandatory.
The
frequency
alloca-
tion
table
specified
frequency
bands
for
specific
uses
in
order
to
minimize
interference

among
stations.
See
Federal
Communications
Commission,
International
Telegraph
Union.
InternationalInformation Systems Security Cer-
tification Consortium
ISC2.
A
nonprofit
corporation
established
in
1989
to
develop
certification
programs
for
security
professionals
working
in
the
informations
services

field.
/>International Intellectual Capital Codes Associa-
tion
IICCA.
Anot-for-profit
association
tasked
with
defining
a
comprehensive
lexicon
of
skills
of
inter-
est
to
industries
and
users
for
employment/employee
matching
through
the
iCAP
Catalog
and
the

Intellec-
tual
Capital
Inventory
(iCAP)
system.
IICCA
is
re-
sponsible
for
the
development, maintenance,
and
uniformity
of
the
iCAP
Catalog.
See
iCAP.
International
Internet
Association A
fee-based
In-
ternet service that provides access
to
more
than

20,000
databases
from
around
the
world.
InternationalInternetIndustrialAssociation lIlA.
A
professional
association
of
Internet
Service
Provid-
ers
(ISPs),
Web
developers,
software
developers
and
others
directly
influencing
or
being
influenced
by
the
development

of
the
Internet.
The
IlIA
is
concerned
with
issues
such
as
the
addition
of
a
larger
available
base
of international
Top
Level
Domains
(TLDs).
/> />InternationalMobile SubscriberIdentity
IMSI.
An
lTU-
T identification
number
assigned

by
a
wireless
carrier
to
a
mobile
station
to
uniquely
identify
the
sta-
tion
locally
and
internationally.
InternationalNetworkforDevelopmentInforma-
tion Exchange
INDIX.
Acoalition
for
organizations
involved
in
development
in
information
exchange.
INDIX

developed
the
CEFDA
standards
for
data
ex-
change
and
participated
in
the
development
of
the
International Development Markup Language
(IDML).
See
IDMLlnitiative.
/>International Organization for Standardization
(International Standards Organization)
ISO.
An
important
international
standards-setting
body
which
has
produced

many
of
the
specifications
and
docu-
ments
used
by
telecommunications professionals.
ISO
is
familiar
to
many
through
its
ISO-9000
series
of
quality
assurance
specifications.
ISO-9000
stan-
dards
can
be
summarized
as

"Say
what
you
do,
then
do
what
you
say,
and
get
it
certified,
if
necessary."
/>International
Radio
Consultative
Committee
CCIR.
A standards
and
regulatory-recommending
body
founded
in
1927,
descending
from
the

Interna-
tional
Radiotelegraph
Conference
in
1906,
in
connec-
tion
with
the
International
Telegraph
Union.
This
or-
ganization
was
formed
in
response
to
public
broad-
casts
over
radio
waves
in
the

early
1920s.
See
Inter-
national
Telecommunication
Union
(ITU-R).
InternationalRadiotelegraphic Convention
One
of
the
early
international
gatherings,
resulting
from
the
growth
of
telegraphy,
resulted
in
a
multinational
con-
sent
agreement
regarding
Protocol

and
Service
Regu-
lations
that
was
documented
in
November
1906.
The
convention
was
to
be
entered
into
force
in
July
1908
by
Great
Britain,
Germany,
Austria,
Hungary,
Den-
mark,
and

a
number
ofother
European
nations,
Ja-
pan,
Argentine
Republic,
Brazil,
Chili,
Uruguay,
Rus-
sia,
Turkey,
Persia
(now
Iran),
the
U.S.,
and
Mexico.
The
convention
defined
various
types
of
telegraphic
establishments

common
at
the
time,
including
coast
and
ship
stations,
and
delineated
operating
parameters
to
ensure
cooperation
in
the
use
of
telegraphic
trans-
missions
and
designated
frequencies,
responses
to
distress
signals,

telegraphic
charges,
and
other
tele-
graphic
matters
of
international
importance.
See
Ra-
dio
Communication
Laws
of
the
United
States.
International Society for Measurementand Con-
trol
ISMC.
Formerly
the
Instrumentation
Society
of
America
(ISA),
ISMC

is
a
nonprofit
professional
or-
ganization
supporting
manufacturers
and
engineers
involved
in
the
theory,
design,
manufacture,
and
use
of
measurement
and
control
instruments
and
com-
puter
systems.
See
Instrumentation,
Systems,

and
Automation
Society.
http:/www.isa.org
/>499
© 2003 by CRC Press LLC
Fiber
Optics
Illustrated
Dictionary
International Special Committee on Radio Inter-
ference
CISPR.
An
international committee
with
members
from
a
broad
spectrum
of
the
radio
com-
munications/engineering
industry
who
work
to

pro-
mote
international
agreement
on
aspects
of
radio
in-
terference
to
facilitate
international
trade.
CISPR
is
composed
ofa
number
of
international
organizations
plus
each
National
Committee
of
the
International
Electrotechnical

Commission
(IEC).
Through conferences
and
subcommittees,
CISPR
promotes
and
produces
information
guidelines,
sta-
tistical
methods,
and
standards
related
to
the
protec-
tion
of
radio
reception
from
interference
from
con-
sumer
goods

and
industrial
equipment,
electrical
sup-
ply
systems,
and
broadcasting
equipment.
CISPR
es-
tablishes
limits
and
requirements
for
immunity
to
in-
terference
and
takes
into
consideration
safety
regu-
lations
as
they

affect
interference
suppression
of
elec-
trical
equipment.
Of
particular
interest
to
telecommu-
nications
are
CISPR
publications
on
electromagnetic
compatibility (EMC) and emission standards.
/>InternationalSpeech CommunicationAssociation
ISCA.
A
nonprofit
organization
promoting
interna-
tional
speech
communication,
science,

and
technol-
ogy
originally founded
in
1988
as
the
European
Speech
Communication
Association,
ISCA
was
es-
tablished
in
1999.
It
is
now
an
independent,
self-sup-
porting
organization.
ISCA's
interests include
re-
search

in
synthetic
speech
development
and
process-
ing.
/>International Switching Center
ISC.
A
gateway
exchange
whose
function
is
to
switch
telecommuni-
cations traffic
between
national
and
international
countries.
International
Telecommunication Regulations
ITR.
A
set
of

international
regulations
intended
to
supplement
the
International Telecommunication
Convention
while
also
recognizing
the
individual
rights
of
nations
to
regulate
their
telecommunications
sectors.
The
ITR
framework
seeks
to
promote
the
efficiency,
harmony,

and
evolution
of
global
telecom-
munications
through
established
general
principles
for
international
telecommunication
transport
media
and
services
offered
to
the
public.
Draft
proposals
of
the
ITR
were
presented
at
the

world
Administrative
Telegraph
and
Telephone
Conference
in
Melbourne,
Australia,
in
1988
per
a
resolution
of
the
Plenipoten-
tiary
Conference
of
the
International
Telecommuni-
cation
Union
(ITU).
International Telecommunication Union
ITU.
A
significant,

influential,
global
United
Nations
stan-
dards
agency
descended
from
the
International
Tele-
graph
Union.
The
lTU,
headquartered
in
Geneva,
Switzerland,
provides
extensive
publications,
pro-
motes
communication,
sponsors
international
meet-
ings

and
conferences,
disseminates
news,
and
devel-
ops
standards
and
regulations.
The
lTU
oversees
a
number
of
subgroups,
called
sectors
(see
chart).
The
lTU
is
involved
in
a
number
of
important

com-
munications
venues
for
discussion
and
the
dissemi-
nation
of
findings.
Examples
include:
500
•
The
publication
of
the
lTU
Operational
Bul-
letin
every
2
weeks
to
report
on
the

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

annexes.
• The organization
of
the World Radio-
communication
Conference
(WRC)
to
admin-
ister
international
agreements
in
wireless
tele-
communications
technologies.
•
The
organization
of
the
World
Telecommuni-
cations Standardization
Assembly
to
deter-
mine
needs

and
priorities
related
to
standards
development
and
dissemination.
The
convening
of a
Plenipotentiary
Confer-
ence
every
4
years
(1998,
2002,
etc.),
an
im-
portant meeting
ground
for
member
states
where
decisions
on

direction
and
policy
are
made
and
previous
actions
reviewed
and
de-
bated.
The
1998
conference
was
characterized
by
calls
for
greater
involvement
of
the
private
sector
in
lTU
activities.
When

the
council
is
not
convened,
administration
and
oversight
of
the
lTU
is
handled
by
the
lTU
Council.
See
Telecommunication
Standardization
Bureau.
For
abrief
description
oflTU-T
history,
see
International
Telegraph
Union.

For
series
lists
and
individual
rec-
ommendations,
see
Appendix
C
and
alphabetized
lists
under
letter
designations.
/>International Telegraph Union
lTU.
An
old
and
influential
organizing
and
standards-recommending
body
formed
in
1865
when

the
telecommunications
industry
was
beginning
to
boom.
The
lTU
was
cre-
ated
in
response
to
the
need
for
cooperation
and
for-
mal
agreements
related
to
the
installation
and
use
of

multinational
telegraph
systems.
Twenty
participat-
ing
countries
signed
the
first
International
Telegraph
Convention.
After
the
invention
of
the
telephone,
the
Telegraph
Union
drew
up
recommendations
for
legislation
gov-
erning
international

telephony.
Radio
communica-
tions
began
to
develop,
so
the
Telegraph
Union
con-
vened
a preliminary
radio
conference
in
1903
lead-
ing
to
the
Radio
Regulations
and
founding
of
the
In-
ternational

Radio
Consultative
Committee
(CCIR).
In
1934,
the
name
was
broadened
to
International
Telecommunication
Union.
It
became
an
agency
of
the
United
Nations
in
October
1947,
and
the
head-
quarters
was

transferred
from
Berne
to
Geneva
in
1948.
The
Union
later
became
known
as
the
CCITT,
as
there
were
a
number
of
cels
set
up
for
different
areas
of
communication
in

the
1920s;
the
CCIT
and
the
CCIF
were
amalgamated
in
1956.
In
1992,
an
important
conference
took
place
in
which
the
organization
was
evaluated
with
the
aitp
of
up-
dating

it
to
align
with
the
complex,
changing
envi-
ronment
of
current
and
future
technologies.
The
or-
ganization
has
recently
been
renamed
International
Telecommunication
Union
(ITU)
because
the
funda-
© 2003 by CRC Press LLC
International Traffic in Arms Regulations

ITAR.
Rules
issued
by
the
U.S.
State
Department,
under
the
authority
of
the
Arms
Export
Control
Act,
to
control
the
export/import
ofdefense-related articles
and
ser-
vices,
including
information
security
systems
such

as
cryptographic
systems
and
TEMPEST
suppression
technology.
International
World
Wide
Web
Conference
Committee
See
World
Wide
Web
Conference
Committee.
ITV-D
Telecom.
Development Sector
Facilitates
global
telecommunication
development
by
providing
organizing
and

coordinating
expertise
and
assistance.
The
lTV
-D
works
through
conferences,
study
groups,
the
Telecommunication
Development
Advisory
Group,
and
the
Telecommunication
Development
Bureau
(BDT).
mental
objectives
of
the
original
organization
remain

essentially
the
same
today
as
they
were
over
100
years
ago,
and
the
convergence of
the
many
media
and
communications
technologies
through
digital
trans-
mission
has
united
many
formerly
separate
areas.

(Source:elTU-TWeb
site
history.)
In
Canada,
communication
with
the
lTD
is
accom-
plished
through
the
Canadian
National
Organization
for
the
lTV
(CNO/ITD-
T)
and
the
Steering
Commit-
tee
on
Telecommunications
of

the
CSA
(CSA/SCOT).
See
International
Telecommunication
Union;
Morse,
SamueIB.F.
ITV-R
Radiocommunication Sector
Descended
from
the
International
Radio
.Consultative
Committee
(CCIR),
this
is
the
arm
of
the
lTV
responsible
for
researching
technical

and
related
regulatory
issues.
It
regulates
ground-
and
space-based
radio
frequency
telecommunications.
ITV-T
Telecom.
Standardization Sector
Founded
in
March
1993,
ITV-
T
replaces
the
International
Telegraph
and
Telephone
Consultative
Committee
(CeITT).

The
ITV-
T
endeavors
to
ensure
efficient
and
on-time
production
of
high
quality
standards
covering
all
fields
of
telecommunications
with
the
exception
of
radio,
which
is
handled
by
ITV-R.
The

work
of
the
ITV-T
is
handled
by
numerous
study
groups
and
is
documented
in
tens
of
thousands
of
papers.
Presently
more
than
2500
standards
recommendations
are
in
force
that
form

a
framework
for
global
communications.
internet
When
spelled
with
a
lowercase
"i,"
generi-
cally
refers
to
an
interconnection of
two
or
more
data
networks.
While
individual
networks
may
be
con-
nected

in
any
number
of
ways,
it
is
common
to
inter-
connect
them
through
the
Open
Systems
Interconnect
(OSI)
model
as
it
ensures
a
good
level
of
compatibil-
ity
with
existing

technologies
and
supports
interoper-
ability
among
a
variety
of
types
of
systems.
See
In-
ternet.
Internet
A global communications
community
of
more
than
60,000
cooperating
networks,
evolving
in
the
early
1980s
out

of
ARPANET,
now
known
as
the
Internet or colloquially
as
the
Net.
The
Internet
consists
ofa distributed
network
of
tens
of
millions of computers linked together through
small
and
large
communications
services
providers.
By
early
1995,
the
Internet

had
more
than
4
million
hosts
and
the
term
was
officially
defined
by
the
Fed-
eral
Networking
Council.
The
Net
is
defined
in
the
Telecommunications
Act
of
1996
and
published

by
the
Federal
Communications
Commission
(FCC)
as
I
"

the
international computer network of both
Federal
and
non-Federal interoperable packet
switched
data
networks."
The
evolution
of
the
Net
has
been
influenced
by
a
broad base of technical and lay interests
and

an
equally
wide
range
of
commercial
and
public
inter-
ests.
The
vocal
promoters
of
the
Net
as
a
universal
access
communications
medium
to
serve
the
public
good
have
been
joined

by
commercial
interests
seek-
ing
a
way
to
use
the
Net
to
further
private
and
public
business
interests.
In
the
early
days,
the
Net
had
a
high
proportion of
users
in

technical
and
scientific
fields
and
focused
on
cooperative
communication
and
re-
search.
Since
the
mid-l
990s,
an
overwhelming
influx
of
commercial
vendors
has
changed
the
character of
the
Net,
but
there

has
also
been
a
large
growth
in
co-
operative
nonprofit
and
community
organizations.
In
1993,
the
United
Nations
and
the
U.S.
White
House
came
online,
thus
changing
the
ways
to

access
and
think
about
politics.
Global
doors
have
opened
up
to
people
doing
genealogical
studies
and
people
are
re-
discovering
friends
they
haven't
seen
since
elemen-
tary
school.
The
phone

network
is
undergoing
sub-
stantial
changes
due
to
competition
from
long-dis-
tance
email
and
chat
resources
that
are
available
on
the
Internet without long-distance
phone
costs.
The
impact
of
the
Internet
on

communications
ven-
ues
and
global
culture
is
highly significant
and
will
likely
exceed
the
changes
brought
about
by
the
in-
dustrial
revolution.
The
information
glut
and
impact
on
personal privacy
will
be

far-reaching
as
well.
Speculations
about
the
emergence
of
the
Net
as
a
fonn
of
digital
intelligence
may
not
be
farfetched,
and,
with
the
cooperative
communication
possible
among
sci-
entists
and

interested
lay
persons,
research
will
move
forward
at
an
unprecedented
rate.
See
ARPANET,
Telecommunications
Act
of
1996,
RFC
1958.
Internet 2Aconsortium of
more
than
100
academic
and
nonacademic
organizations
working
to
develop

a vision and implementation plan for the next
Sector Notes
ITU-T
Subgroups
(Sectors)
Abbrev.
501
© 2003 by CRC Press LLC