Fiber Optics Illustrated Dictionary - Part 14 pps

Fiber
Optics
Illustrated
Dictionary
BITNET, BITNET-NJE Because It's
Time
Net-
work.
An international, cooperative,
academic
net-
work
established
in
1981
by
Ira
H.
Fuchs
(City
Uni-
versity of
New
York)
and
Greydon
Freeman
(Yale
University).
It
began

as
a cooperative project
at
the
City
University of
New
York,
with
Yale
as
the
first
outside
connection
through
a
leased
telephone
line.
It
ran
originally
on
ffiM
mainframes and Digital
VAXes
communicating
through
EBCDIC

formats.
From
there,
it
spread
across
the
U.s.
and
became
in-
ternational
when
it
was
joined
by
the
European
Aca-
demic
and
Research
Network
(EARN)
in
1982.
A
grant
from

ffiM
in
1984
helped
establish
support
ser-
vices
for
BITNET
in
the
U.S.
BITNET
promoted
the
noncommercial
exchange
of
research
and
education information
and
was
orga-
nized
as
a
nonprofit
corporation

in
1987.
By
1991,
BITNET
included
almost
1500
organizations
in
49
countries
and
for
a
while
was
the
world's
largest
aca-
demic
network.
Participation
declined
thereafter
due
to
the
rapid

growth
of
the
Internet
and
BITNET's
in-
herent
interactivity limitations.
In
the
late
1980s,
it
was
merged
with
The
Computer+Science
Network
(CSNET)
to
form
the
Corporation
for
Research
and
Educational
Networking

(CREN).
In
the
end,
CREN
recommended
to
its
members
that
BITNET
depen-
dency
be
tenninated
by
December
31,
1996
in
favor
ofother
network
systems,
primarily
the
Internet.
BITNET
is
based

on
an
ffiM
communications
pro-
tocol
called
Network
Job
Entry
(NJE),
which
made
it
practical
to
connect
mainframe
computers
through
telephone
circuits.
It
uses
a
store-and-forward
system
of
transmitting
information

through
nodes
on
the
sys-
tem.
See
Network
Job
Entry,
RELAY,
UUCP.
BITNIC
BITNET
Network
Information
Center.
A
support
center
for
administering
BITNET
computer
networks
initially established
with
the
aid
of

fund-
ing
from
ffiM
in
1984.
After
1987,
funding
was
mem-
ber-based
and
volunteer-supported.
See
BITNET.
BITS
See
Base
Information
Transport
System.
bits per
second
bps.
A
very
common
means
of

de-
scribing
data
transmission per
second
unit of
time.
A
megabit
per
second,
or
Mbps,
represents
a
million
bits
per
second.
Common
consumer
modems
operate
at
data
rates
of
about
9600
to

28,800
bits
per
second.
T
1,
fiber
lines,
and
other
higher
speed
protocols
and
media
can
transmit
at
much
higher
rates.
BIU
See
basic
information
unit.
BL
1.
bilateral.
Having

two
sides.
2.
See
bit
line.
black
In
politics,
a
designation
for
secret
and/or
clas-
sified
information
or
activities.
The
designation
has
significant
impact
on
telecommunications
in
a
num-
ber

of
ways.
Black
operations
may
be
used
to
tap
into
communications
systems
to
eavesdrop
on
conversa-
tions
or
data
transfers.
Computing
systems
designated
for
black
operations
are
typically
equipped
with

spe-
cial
encryption
systems
and
code-creating
keyboards,
wheels, algorithms
and
other
means
of
encoding
messages
or
data.
Fiber
optic
connections
are
favored
over
electrical
connections
for
secured
cable
installations
because
it

is
harder
to
tap
into
fiber
optic
connections
without
122
detection.
Wired
connections
can
be
tapped
with
sen-
sitive
instruments
that
sense
emanations
from
the
wire
without necessarily
touching
the
wire.

A
fiber
optic
transmission doesn't
emit
electromagnetic radiation
in
the
same
way
as
electrical connections.
The
only
practical
ways
to
tap
into
a
fiber
optic
connection
are
(
1)
to
bend
the
filament

to
cause
the
light
to
escape
the
reflective cladding layer
(in
which
case
the
loss
of
power
of
the
light
beams
could
be
detected
beyond
the
point of
the
tap)
or
(2)
to

insert aclandestine
tap
segment
in
the
link,
which
would
involve temporary
disconnection of
the
existing link (which
may
trig-
ger
an
alarm),
and
would
require
higher technical
ex-
pertise
and
much
more
precise components
than
a
typical

copper
wire
connection.
See
encryption.
black body Atheoretical
body
which
absorbs
all
in-
cident
light
with
no
reflection
and
consequently
ap-
pears black (without light)
at
all
wavelengths.
Black
Box
Aregistered trademark of
The
B
lack
Box

Corporation
of
Pittsburgh,
PAl
black
box
1.
colloq.
A
device
whose
internal
work-
ings
are
obscure
or
obscured.
That
is,
the
outside
may
not
indicate
what
is
inside,
or
how

it
works.
2.
A
de-
vice
that
is
used
by
a
lay
person without technical
knowledge
of
its
construction
or
functioning.
3.
A
type
ofclandestine
phone
interface
device
used
in
a
central office

to
gain
unauthorized
access
to
phone
services
by
obscuring
the
fact
that
a
long-distance
call
had
been
answered.
See
blue
box,
red
box.
black
box
design A
design
model
for
inputs

and
out-
puts which function independently of
the
various
ways
the
internal
components
might
be
configured.
F
or
example,
a converter
or
transformer
for
match-
ing
two
types
of
signals
might
be
specified,
with
lee-

way
given
to
a manufacturer
as
to
the
best
way
to
implement
and
build
the
hardware
itself.
black
hole
1.
A theorized invisible
(thus
perceived
as
dark)
region
in
space with a small diameter
in
re-
lation

to
its
intense gravitational
field.
Ablack
hole
could
perhaps result
from
the
collapse ofa massive
star,
in
which
the
escape
velocity
equals
the
speed
of
light.
2.
colloq.
A
fictional
area
into
which
things

dis-
appear
when
they
can't
be
found,
and
those
looking
for
them
are
sure
they
should
be
"right there."
3.
In
networks
and
computer
systems
in
general,
a point
in
the
transmission

link
where
data
went
in
and
ap-
parently didn't
come
out.
Black
hole
also
refers
to
a
metaphorical repository
for
lost
data.
Disappearing
into a black hole
may
also
be
jargonistically
de-
scribed
as
disappearing

into
the
ether,
into
the
bit-
stream,
or
into
the
bit
bucket.
black
level
Areference
level
on
a
display
device
cor-
responding
to
the
lowest
possible
luminance
setting,
which
typically

appears
as
black
(the
absence
ofil-
lumination), or nearly black, depending
upon
the
characteristics of
the
display
device.
black matrixtubeA
cathode-ray
tube
in
which
black
fills
the
spaces
between
color
phosphors
on
the
in-
side
front

coating of
the
tube.
The
greater contrast
between
the
lit phosphors
and
the
small
surrounding
area
results
in
a picture
that
appears
to
have
crisper,
brighter
colors.
© 2003 by CRC Press LLC
black recording
In
recording
systems
using
ampli-

tude
modulation,
black recording
is
the
correlation
between
the
maximum
power
of
the
transmission
and
the
maximum
density
of
the
recording
device.
In
re-
cording
systems
employing
frequency
modulation,
black
recording

is
the
correlation of
the
lowest
fre-
quency
received
and
the
maximum
density of
the
re-
cording
medium.
The
phrase
applies
to
various
wired
and
wireless
facsimile
machines, printers, electronic
photocopiers,
etc.
See
black transmission.

blacktransmission,
AM
In
an
amplitude-modulated
(AM)
image
transmission,
black
means
that
the
great-
est
divergence
in
amplitude
in
the
signal
represents
the
black
tones,
and
the
narrowest divergence
repre-
sents
the

lightest
tones
(or
no
tone
at
all).
In
white
transmission,
the
opposite
is
true.
black transmission, FM
In
a frequency-modulated
(FM)
transmission,
a black transmission
means
that
the
lowest
frequency
corresponds
to
black,
and
the

highest
frequency
corresponds
to
white
or
no
tone;
in
a
white
transmission
the
opposite relationship
is
used.
Black transmission concepts
in
general
can
be
applied
to
image
scanners,
facsimile
machines,
pho-
tocopiers,
etc.

See
black recording
blackjack
When
Samuel
Morse
won
acontract
from
the
u.S.
Congress
in
the
1800s
to
build a telegraph
line
from
Washington,
DC
to
Baltimore,
MD,
he
ini-
tially
tried
to
install

the
lines
underground, alongside
railroad
tracks.
There
were
problems
with
the
line,
however,
and
the
wires
were
subsequently
suspended
from
poles.
To
this
day,
millions of
miles
of
commu-
nications
cables
are

installed
on
utility
poles.
Since
the
poles
were
subject
to
weathering, they were
coated
with
creosote,
a
preservative
derived
from
coal
tar
that
came
to
be
called blackjack.
It
is
still
used
to

prevent
dry
rot
and
insect infestations.
Blake, Francis, Jr. (1850-1913) An
American
inven-
tor,
physicist,
and
photographer
who
became
ap-
pointed
to
the
u.S.
Coast
Survey
in
1866,
Blake
was
talented
in
mathematics
and
became

skilled
in
tele-
graphy,
astronomy,
and
hydrography.
Upon
leaving
the
Coast
Survey
in
1878,
he
pursued
his
creative
ideas
and
invented
abetter
telephone
transmitter.
He
subsequently patented numerous other inventions.
Emile
Berliner
was
later

to
make
practical
improve-
ments
to
some
of
the
microphone
technology
devel-
oped
by
Blake.
A number ofBlake's papers
are
ar-
chived
by
the
Massachusetts
Historical
Society,
Bos-
ton.
See
Berliner,
Emil;
Blake

telephone;
Blake
trans-
mitter;
telephone
history.
Blake telephone A historic magneto telephone,
known
as
the
Blake Transmitter,
which
became
the
first
standard telephone installed
by
the
Bell
Tele-
phone
Company
of
Canada.
It
incorporated a
mag-
neto
generator,
which

was
cranked
to
ring
the
cen-
tral
switching
office,
and
a better quality transmitter
invented
by
Francis
Blake,
Jr.
A
wet
battery
provided
power
to
the
system.
The
quality of
the
system
was
important

to
furthering
Bell's
success
as
a telephone
company.
See
Blake
transmitter.
Blake transmitterA
pioneering
telephone
transmitter
designed
by
Francis
Blake,
Jr.,
in
1878
so
the
diaphragm
could
vary
the
strength of
an
already established

cur-
rent
from
a
battery,
rather
than
generating
energy
by
means
of
electromagnetic induction,
as
in
earlier
models,
thus
producing
astronger
sound.
He
received
three
related
patents
for
carbon
transmitting
technolo-

gies
in
1881.
blank
1.
A transmissions
gap,
one
in
which
no
sig-
nal or data is coming through.
2.
A space or
nonprinted
area
on
paper.
3.
Aspacer
used
to
format
a blank
area
in
HTML
documents
for

display
on
the
Web.
It
may
be
created with
(1)
a blank
image
file,
(2)
a
<PRE>
(preformatted) tag, or
(3)
an
&nbsp
(nonbreaking
space)
tag.
4.
An
advancing
key
on
a
teletype, typewriter, typesetter,
label-maker,

or
other
device
such
that
an
unprinted
area
is
established.
The
word "space"
is
often used interchangeably with
blank.
blanking
In
a
display
device,
such
as
a cathode-ray
tube
(CRT),
the
interval
during
which
part

or
all
of
the
display
is
suppressed.
Blanking
is
used
to
sup-
press
artifacts
from
the
display
sweep
of
an
electron
gun.
The
sweeping
ofa
screen
is
often
a
repeated

zig-
zag,
but
the
part
of
the
transmission
intended
to
be
seen
is
displayed
on
the
straight
sweep
(usually
the
horizontal
sweep
),
and
the
beam
drops
to
the
next

line
as
it
moves
back
to
the
other
side,
ready
to
sweep
again
(horizontal blanking).
It
is
somewhat
like
the
line
feed
and
carriage return
on
a
typewriter;
as
the
carriage
sets

the
typing
position back
and
down
to
the
beginning
of
the next line,
it
shouldn't make
marks
on
the
page.
See
blanking
pulse.
blanking interval, blanking time
The
period
dur-
ing
which
a display
is
suppressed, usually
to
enable

an
electron
gun
to
return
to
the
next display
position.
See
blanking,
cathode-ray
tube,
frame,
sweep.
blanking pulse A
mechanism
for
suppressing a
dis-
play,
usually
on
a cathode-ray
tube.
It
is
sometimes
accomplished by means
of

a positive
or
negative
square
wave.
A
series
ofpulses
can
be
combined
to
create ablanking
signal
that
is
synchronized
with
the
sweep.
blazed, blazing
1.
Characterized
by
a
somewhat
pe-
riodic bright illumination, that
is,
sudden

orundulat-
ing
moments
of greater light often associated
with
heat,
such
as
a
forest
fire,
torch,
or
firing
line
of
mus-
kets.
2.
Illumination associated with
sustained,
intense heat, such
as
a well-stoked
furnace
or
the
desert
sun.
3.

Having
been
marked with a
short
slash,
slit,
or
cut
as
an
identifier, often
as
part ofa
group
or
series,
as
a
line
of
blazed trees indicating a
path.
4.
A
fabrication
with
a
regular,
periodic "sawtooth"
struc-

ture
that facilitates
the
filtering
or
concentration of
energy
through controlled diffraction,
as
in
a blazed
grating.
See
blazed
grating.
blaze angle
In
ablazed grating,
the
incline of
the
in-
dividual
"sawtooths"
in
relation
to
the
mean
grating

surface.
The
angle
is
designed
to
reflect radiant
en-
ergy
ofa desired wavelength
in
controlled
ways
to
serve
as
a filtering
mechanism.
When
"holographi-
cally"
recorded
and
etched
in
an
interference
grating,
the
blaze

angle
can
be
established within certain tol-
erances
but
is
not
as
precise
as
a
machined
grating
123
•
'.,
•.
,;
•.
·.1

·,

1,
li}' ,
~:~
© 2003 by CRC Press LLC
Fiber
Optics

Illustrated
Dictionary
due
to
the
sinusoidal
shape
of
the
peaks
and
troughs
in
a photographically etched grating.
Consistency
of
the
blaze
angles
of
individual
facets
is
usually
de-
sirable.
See
Brewster's angle, incidence angle,
Littrow
configuration.

Blazing
creates
asawtooth
design
in
agrating that
selectively reflects
wavelengths,
thus
acting
as
a
con-
centrator
or
filter.
The
blaze angle
can
be
designed
to
control
the
angle
of
incidence
of
the
reflected light

beam,
thus
enabling
the
grating
to
be
Htuned"
to
cer-
tain
frequencies.
In
the
asymmetric sawtooth configu-
ration,
the
direction
of
the
light
source
input
is
impor-
tant for efficient exploitation
of
the
angle
of

refrac-
tion.
BLISS
Broadband
Lightwave
Sources
and
System.
An
ACTS
project
to
bring
to
maturity
key
aspects
of
photonic
networks
and
to
demonstrate
their
practi-
cal
implementation.
Specific
concerns
include

de-
tailed
studies
of
optical
crosstalk
and
dynamic
range.
OEIC
receiver
chips
are
studied
through
PON
and
ATM
ring
solutions
with
verification
and
compari-
son
to
commercial
systems.
Some
key

components
include
photonic
ICs,
pulse
sources,
a
variety
of
types
of
lasers,
semiconductors,
and
other
relevant
devices
and
technologies.
Trials
were
planned
for
a
univer-
sal
interface
for
different
traffic

types
and
physical
media
(copper,
optical
fiber,
etc.)
to
provide
ATM
access.
BLISS
components
are
being
used
in
other
ACTS
projects.
See
BROADBANDLOOP,
UP-
GRADE,
and
WOTAN.
Bloch,
Felix (1905-1983) A
Swiss

mathematician
and
physicist,
Bloch
was
associated
with
a
remark-
able
who's
who
list of
the
most
renowned
physicists
of
the
early
20th
century.
He
did
graduate
work
un-
der
quantum
theorist

Werner
Heisenberg
in
Leipzig,
Germany,
where
his
graduate thesis, published
in
1928,
made
an
important
contribution
to
the
knowl-
edge
of
electron
conduction.
In
Zurich,
Switzerland,
where
Bloch
worked
for
Wolfgang
Pauli,

he
made
his
fIrst
unsuccessful
attempts
to
formulate
a
theory
of
superconductivity
but
got
a
start
in
understanding
dif-
ferent
ways
to
approach
the
problem.
He
then
trav-
eled
to

the
Lorentz Foundation,
where
he
studied
theories
of
electric
conductivity,
and
then
studied
fer-
romagnetism
at
the
University of Leipzig. Bloch
worked
with
the
highly
regarded
Niels
Bohr
as
a
Fel-
low
of
the

0rsted
Foundation.
While
at
the
Institute
in
Copenhagen,
he
described
theoretical
relationships
between
classical
and
quantum
theory.
Fermi
encouraged
Bloch
to
consider
both
theory
and
practice
and,
in
1934,
Bloch

moved
thousands
of
miles
to
Stanford
University
where
he
taught
theo-
retical physics and gave seminars with Robert
Oppenheimer.
In
1936,
Bloch
sought
to
create
a
neutron
source
for
the
research
ofparticle
physics.
Together
with
Luis

Alvarez,
he
began
work
with
U.S.
Berkeley)
cyclo-
tron
to
determine
the
magnetic
moment
of
the
neu-
tron.
Thus,
he
resolved
to
build
a
cyclotron
at
Stan-
ford,
a project initiated
in

1939.
After
a brief
tenure
at
the
Los
Alamos
Manhattan
Project,
Bloch
worked
on
theoretical
studies
in
radar
and
conducted
micro-
wave
reflectivity
research
at
the
Harvard
Radio
Re-
search
Laboratory.

Returning
to
Stanford
in
1945,
he
had radio equipment built
and
cooperated with
Purcell
in
dividing
up
the
research. This led
to
progress
in
nuclear
magnetic
resonance
(NMR).
Bloch
and
Purcell
were
awarded
the
1952
Nobel

Prize
in
physics.
Bloch
was
one
of
the
Stanford
members
who
encouraged
the
Atomic
Energy
Commission
to
support
construction
of
the
Stanford
Linear
Accelera-
tor
Center
(SLAC).
In
his
later

years
he
returned
to
his
country
of
birth.
See
Hansen,
William.
·
Bloch's theorem of superconductivity
The
lowest
state
ofa
quantum
mechanical
system,
in
the
absence
ofa
magnetic
field,
can
carry
no
current.

B
reflective
surface
Blaze
Angle
in
Fiber
Grating
reflective
surface
A
blaze condition
In
a
semiconductor
component,
a
configuration
in
which
a
corrugated
blazing
structure
is
exhibiting
diffractive
control
over
incoming

wave-
lengths
such
that
they
are
selectively
filtered
or
passed
through
the
structure.
This
is,
in
part,
a
function
of
the
shape
of
the
blazed
grating
along
with
the
layers

associated
with
the
grating.
See
blazed,
blazed
grating.
blazed grating A
corrugated
selectively reflective
surface
in
which
the
grooves
are
regularly
asymmet-
ric.
The
shape
of
the
pattern
of
grooves
or
corruga-
tions

is
sometimes
called
a
sawtooth.
In
this
type
of
grating,
the
shape
of
the
teeth
and
their
orientation
have
higher
significance
than
the
grating
period
(al-
though
very
fine
teeth

will effect diffraction effi-
ciency).
Blazed
gratings
can
be
mechanically
or
pho-
tographically
fabricated
but
are
generally
mechani-
cally
ruled,
since
the
sinusoidal
characteristic of a
photographic
interference
grating
doesn't
lend
itself
to
blazing.
The

Hubble
telescope
utilizes a
blazed
grating.
See
blaze
angle,
echelle grating, grating,
ruled
grating.
blaze
wavelength
For
a
given
blazed
grating
and
its
associated
layered
components,
in
a
given
index
dif-
fraction
order,

the
wavelength
for
which
the
relation-
ship
between
diffraction
intensity
and
wavelength
is
at
its
maximum
efficiency.
See
Maxwell's
equations.
BLEU
Belgo-Luxembourg
Economic
Union.
A
co-
operative
arrangement
between
Belgium

and
Luxem-
bourg,
established
in
1921,
to
support
currency
bases
and
legal
tender
between
the
two
countries.
blind transfer,
cold
transfer
The
transfer
ofa
call
without
seeking
the
identity
of,
or

receiving
informa-
tion
about,
the
caller.
blind
zone
A
zone
where
there
are
no
transmission
signals.
A
skip
zone
is
one
type
of
blind
zone.
See
zone
of
silence.
124

© 2003 by CRC Press LLC
block check
character
BCC.
An
error-checking
technique developed
for
early teletypewriters
in
which
a
control
character
is
appended
to
blocks
for
longitudinal
checking
and
CRC.
In
packet
network-
ing,
as
a
packet

is
assembled,
the
data
is
processed
to
create
a
BCC,
which
is
then
incorporated
into
the
packet,
checked
at
the
receiving
end,
and
acknowl-
edged
(ACK)
or
not
acknowledged
(NACK)

if
it
does
not
match.
The
data
can
then
be
resent
until
the
BCC
matches
or
until
the
process
is
stopped.
BCC
is
used
in
a
variety
of
implementations,
including

most
polled
protocols.
block cypher A
type
of
encryption algorithm
that
breaks
plaintext
data
into
segments
(usually
ofa
fixed
size)
and
uses
the
same
encryption
key
to
transform
each
segment
into
a
segment

of
ciphertext.
See
Blow-
fish,
SKIPJACK.
blockdiagramA
type
of
visual
communications
aid
that
uses
simple
shapes
to
symbolize
objects,
func-
tions,
relationships,
conditions,
and
processes.
A
flow
diagram
or
flow

chart
is
a
type
of
block
diagram
in
which
specific
shapes
have
been
standardized
to
have
certain
meanings
within
the
context
of
the
diagram.
Rectangles, diamonds,
and
arrows
are
commonly
used.

blocktransfer
The
process
of
moving
data
in
a
block,
instead of
in
individual bits.
Double
buffering,
in
which
a
screen
of
information
or
block
of
data
is
built
in
the
background
and

then
instantly
presented
or
dis-
played
by
transferring
it
from
one
area
of
memory
to
another,
is
a
type
ofblock transfer
commonly
used
to
reduce
screen
display
delays.
Various
file
transfer

protocols
make
use
of
block transfer
techniques,
of-
ten
reducing
the
size
of
the
block
if
many
errors
are
occurring.
blocking
1.
Preventing entry/exit
or
transmission
through.
2.
Holding
until
time
or

space
is
available,
as
in
a
queue,
or
until
the
data,
person,
or
object
can
be
turned
back.
3.
A
circumstance
in
which
a
call
can-
not
be
completed
(the

exchange
may
be
overloaded
or
the
line
busy).
See
grade
of
service,
call
abandons.
4.
Deliberate
exclusion
of
certain
parties
from
cer-
tain
numbers
(such
as
prevention of
900
calls,
long-

distance
calls,
etc.)
5.
In
business,
an
illegal practice
preventing
others
from
engaging
in
fair
competition.
6.
In
vacuum
tubes,
creating
very
high
negative
grid
bias
to
lower
the
plate
current

to
zero.
blocking capacitor, blocking condenser A
device
in
a
circuit
that
blocks
direct
current
(DC)
while
per-
mitting
alternating
current
(AC)
to
pass
through.
blocking probability A performance
measure
de-
scribing
the
likelihood
of
data,
or

ofa
user,
being
re-
jected.
bloom
On
a
cathode-ray
tube
(CRT)
display
device,
the
tendency
ofaphosphor excitation
level
to
create
a 'halo'
effect
of
extra
light
that
spreads
out
beyond
the
area

being
targeted.
This
tends
to
happen
at
higher
intensity
levels
with
lighter
colors.
blooper
1.
Goof,
embarrassing
error,
bungle.
2.
In
transmissions
through
a regenerative
relay,
an
un-
wanted
signal
created

by
the
relay
that
is
not
part of
the
desired
transmitted
communication.
blower
1.
colloq.
A
device
to
blow
a
current
of
air
or
gas,
e.g.,
for
installing
air-blown
fiber.
See

blown
fi-
ber.
2.
Aspeaker
or
blowhom.
Blowfish A 64-bit
(8
bytes) encryption algorithm
developed
by
Bruce
Schneier,
Blowfish
has
become
the
basis
for
a
number
of
encryption
schemes,
includ-
ing
Kent
Briggs'
Puffer,

Harvey
Parisien's
VGP,
and
Philip
Zimmermann's
PGP.
Blowfish
uses
a
variable-
length
key
up
to
448
bits
in
length.
There
may
be
re-
strictions
on
sales
outside
the
U.S.,
due

to
Federal
ex-
port
restrictions.
See
Pretty
Good
Privacy.
blown fiber, air-blown fiber
ABF.
A
fiber
optic
in-
stallation
system
designed
by
British
Telecommuni-
cations
PLC
that
enables
faster,
more
flexible
instal-
lation

and
reconfiguration
offiber
optic
cable
systems
by
literally
blowing
the
fiber
lines
into
a
grouped
tube
cable
hose.
Thus,
existing
or
newly
installed
conduit
can
be
fitted
with
fiber
optic

lines.
This
system
is
often
combined
with
point-to-point
modular connectors that eliminate splicing.
Since
splicing
is
an
exactingjob
in
fiber
optic
installations,
modular
connectors
are
agreat
convenience.
blown fuse A
fuse
with
a
broken
connection,
due

to
some
electrical
abnormality
on
the
circuit
on
which
it
is
installed,
which
might
have
endangered
other
links
in
the
system.
Fuses
typically
cannot
be
reused
and
must
be
replaced

with another
with
the
appro-
priate
voltage.
A
blown
fuse
will
sometimes
show
a
blackened
area
inside
the
glass.
Circuit
breakers
have
superseded
fuses
in
many
types
ofelectrical
wiring,
but
the

phrase
has
remained
and
is
often
used
to
in-
dicate
a tripped circuit
breaker.
See
circuit
breaker,
fuse.
BLS
The
u.S.
Bureau
ofLabor Statistics.
/>BLSR
See
bidirectional line-switched
ring.
BLU
basic
link
unit.
A

generic
term
used
in
a
variety
of
networks,
refering
to
a
basic
transmission
unit
of
control
and
data
information.
Blue Book
standard
1.
A
document
published
by
Digital
Equipment
Corporation
(DEC),

Xerox
Cor-
poration,
and
Intel
Corporation
in
1980
to
provide
information
on
the
Ethernet
protocol
standard,
ver-
sion
1.
2.
The
Blue
Book
or
CD
Plus
standards
are
a
subset

of
the
Orange
Book
standards
originally
based
upon
the
Red
Book
and
Yellow
Book
digital
audio
and
computer
data
optical
recording fonnats.
Blue
Book
is
a
special
case
of
the
Orange

Book
standards
in
which
multisession
data
is
recorded
in
two
blocks
with
one
session
devoted
to
recording
music
and
one
devoted
to
recording digital
data.
Blue
Book
formats
are
supported
by

a
number
ofmajor
audio
and
com-
puter
data
vendors.
Blue
Book
discs
can
be
played
on
audio
CD
players
and
on
more
recent
CD-ROM
drives.
Besides
their
simplicity,
the
Blue

Book
stan-
dards
served
another
purpose
in
preventing
CD
play-
ers
from
misreading
the
type
of
data
on
a
disc
(Or-
ange
Book)
and
trying
to
create
audio
from
computer

data
and
possibly
even
damaging
the
equipment
(if
you've
heard
a
modem
screech
over
a
phone
line,
you
get
the
general
idea).
See
Orange.
blue box
colloq.
A
small
handheld
device

designed
125
© 2003 by CRC Press LLC
Fiber
Optics
Illustrated
Dictionary
to
emit
tones
in
the
same
frequencies
as
touchtone
telephones,
often
used
in
the
1980s
for
connecting
long-distance calls illegally through direct tones
rather
than
dialing.
Typically
a connection

was
es-
tablished
through
normal
means,
usually
through
a
toll
free
800
number
and
then
the
blue
box
was
used
to
disconnect
the
remote
ringing,
without
actually
dis-
engaging
from

the
long-distance
connection.
A
new
connection
could
then
be
established within
about
a
10
second
window,
by
punching
in
appropriate
op-
erator
tones
from
a
keypad
on
the
blue
box.
(Some

individuals
have
even
learned
to
reproduce
some
of
these
tones
by
whistling,
without
having
to
use
a
blue
box.)
Newer
systems
can move
these
tones
out
of
band
or
use
more

sophisticated monitoring
and
trac-
ing
of
suspected
connections
to
reduce
the
possibil-
ity of
abuse.
Blue
boxing
probably originated
in
the
very early
1960s,
and
the
Bell
System
first
apprehended
a
blue
box
user

in
1961.
The
myth
that
blue
boxing
is
done
almost
entirely
by
young
college
students
is
refuted
by
a
report
by
AT&T
that
almost
halfof
those
caught
stealing
phone
services

with
blue
boxes
are
business-
men,
many
of
them
wealthy,
along
with
a
number
of
doctors
and
lawyers.
blue gun
In
a color cathode-ray
tube
(CRT)
using
a
red-green-blue
(RGB)
system,
the
electron

gun
spe-
cifically
aimed
to
excite
the
blue
phosphors
on
the
inside
coated
surface
of
the
front
of
the
tube.
Some-
times
a
shadow
mask
is
used
to
increase
the

preci-
sion
of
this
process,
so
the
green
and
red
phosphors
are
not
affected,
resulting
in
a crisper color
image.
See
shadow
mask.
blue pages A
convention
in
telephone
directories
in
which
government
listings

are
printed
on
pages
with
a
blue
background
to
distinguish
them
from
residen-
tial
and
business
listings.
Online
directories of
gov-
ernment
information
and
email addresses
are
now
sometimes
called
blue
page

listings.
blue wire Acolor
designation
used
by
mM
to
indi-
cate
patch
wires
used
to
correct
design
or
fabrication
errors
in
situations
where
it
is
not
practical
to
recre-
ate
the
board

with
the
corrections.
See
purple
wire,
red
wire,
yellow
wire.
Bluetooth Project A
combined
effort of Ericsson,
mM,
Intel,
Nokia,
and
Toshiba,
formed
in
1998
as
a
special interest
group,
to
develop
a vision
and
path

for
a
single,
universal,
low-cost
wireless
communi-
cations
system
that
allows
easy
access
from
a
wide
variety of
wireless
consumer
devices.
See
Service
Discovery Protocol.
Bluetooth Service Discovery Protocol
See
Service
Discovery
Protocol.
BLV
IBLI

An
operator
call
wherein
the
caller
requests
information
about
the
busy
status
ofa
line
or
requests
an
interruption
ofa
call
on
an
Exchange
Service.
BM
1.
See
benchmark.
2.
See

burst
modem.
BMEWS
Ballistic
Missile
Early
Warning
System.
A
U.S.
Government
long-range
warning
and
tracking
radar
network
designed
to
detect missile
fire
along
the
northern
approaches.
BMP,
.bmp A
file
extension
standing

for
bitmap,
often
126
expressed
as
athree-character
file
name
extension
to
maintain
backward
compatibility
with
operating
sys-
tems
that
can't
use
a longer
file
extension.
Techni-
cally,
bitmap
files
are
monochrome

raster graphics
files.
While
.bmp
is
used
by
some
as
a generic
file
extension
name
for
any
type
ofraster graphics
file,
bitmap
also
has
a specific
meaning
for
a
standard-
ized
file
format.
See

bitmap,
raster.
BN
1.
See
background noise.
2.
See
border
node.
3.
See
bridge
number.
BNC
1.
See
bayonet nut
connector.
2.
See
British
National
Corpus.
BNCC
Base
Network
Control
Center.
The

main
ad-
ministrative central facility
for
network
operations
within
an
organization
or
location.
See
Network
Op-
erations
Center.
BO
1.
body
odor.
See
skunkworks.
2.
See
branch
of-
fice.
board
See
printed circuit

board.
Boardwatch A
good
prosumer-Ievel print
and
Web
publication dealing specifically
with
the
telecommu-
nications industry, particularly the Internet.
/>bobtail curtain antenna A phased-array, bidirec-
tional,
vertically-polarized
wire
antenna,
intended
for
high-frequency transmitting
and
receiving.
BOC
See
Bell
Operating
Company.
body
The
main
informational portion ofa

commu-
nication,
sometimes
sandwiched
as
a
block
between
headers
and
trailers.
Sometimes
called
the
payload.
In
a picture
file,
the
body
is
the
portion
that
carries
the
object
or
raster information
about

the
image.
In
a
word
processed
document,
the
body
is
the
portion
that
contains
the
informational
text
and
accompanying
il-
lustrations. Contrast
with
header.
body, type
In
typography,
the
main
portion
of

the
shapes
that constitute acharacter
set
(typestyle).
The
portion
from
which
ascenders
and
descenders
origi-
nate.
Sometimes
called x-height.
body area network
BAN.
Anetwork based
upon
a
body-worn
communications
network
device.
It
is
usu-
ally wireless,
to

enable mobility, but
may
also
be
wired
if
the
user
is
stationary
(usually
seated
at
a
com-
puter,
telephone, or
games
terminal).
The
trend
in
BANs
is
to
incorporate
them
into
clothing
or

body-
worn
harnesses
to
distribute
the
weight
and
decrease
their visibility.
Boggs,
David
R.
Along
with
Robert
Metcalfe,
the
co-
developer
and
co-builder of
the
first
Ethernet
systems
in
1973
at Xerox
PARCo

Metcalfe and Boggs
authored a frequentlycitedarticle"Ethernet: Distrib-
uted
packet switching
for
local
computer networks"
in
Communications
of
the
ACM
in
July
1976.
See
Ethernet;
Metcalfe,
Robert.
Bohr's correspondenceprinciple
In
an
atomic
sys-
tem,
the
behavior of
the
electrons
must

increasingly
approach that predicted
by
classical physics the
higher
the
quantum
number
of
the
orbit.
bolometerAdetection instrument
for
measuring
the
intensity ofradiant
energy
through
a thermal-sensi-
tive
resistor,
a
type
of
actinometer.
Bolometers
may
be
assembled
in

arrays.
© 2003 by CRC Press LLC
Boltzmann constant
(symb.
-
k)
The
ratio
of
the
uni-
versal
gas
constant,
R,
to
the
Avogadro
constant,
Na.
Named
after
Ludwig
Boltzmann.
Boltzmann, Ludwig (1844-1906)
An
Austrian
ex-
perimenter
who

built
on
the
ideas
of
James
Clerk-
Maxwell,
studying
electromagnetism,
thermodynam-
ics,
and
statistical mechanics. Boltzmann
demon-
strated
a
number
of
Maxwell
's
predictions,
confrrm-
ing
them,
and
published
his
results
in

1875.
The
Ludwig
Boltzmann
Institute
for
Urban
Ethology
in
Vienna
is
named
after
him.
BOM
1.
BASIC
operations
monitor.
A
monitoring,
debugging
tool
for
BASIC
programs.
2.
beginning
of
medium.

A
phrase
applied
to
the
start
ofa
tape
or
other
serial
storage
media.
3.
See
Beginning
of
Message.
BONAPARTE
Broadband
Optical
Network
using
ATM
PON
Access
Facilities
in
Realistic
Telecommu-

nications
Environments.
An
ACTS
project
to
dem-
onstrate
the
viability of
broadband
ATM
PON
as
a
cost-effective
communications
system
and
to
dem-
onstrate
interoperability
between
ATM
mc
island
through
the
Pan European

ATM
Network. See
BROADBANDLOOP,
BOURBON.
bond
n.
1.
To
join,
adhere,
or
unite
into
a
combined
unit
or
system.
Bond
usually
implies
a
semiperma-
nent
or
permanent
adherence,
as
opposed
to

wrap-
ping
a
wire,
which
would
not
be
considered
a
bond.
A
bond
is
often
accomplished
with
a bonding agent
such
as
glue,
weld,
or
solder.
See
fusion
splicing.
bond, electrical
To
form

an
electrical
connection
by
joining
two
conductive
surfaces, usually
metal,
to
provide
a
low-resistance
path
for
the
circuit.
In
elec-
tronics,
wires
are
often
bonded
to
a
small
metallic
pad
on

a
circuit
board.
See
bonding.
bonding
1.
Joining
two
or
more
items
with
adhesive,
weld
or
solder.
In
PC
boards,
there
may
be
a
bond-
ing
pad
on
the
board

or
on
a
chip
for
the
express
pur-
pose
of
providing
sufficient
space
and
electrical
con-
tact
for
a
potential
bond
(usually
solder).
2.
An
in-
verse
multiplexing
specification
described

by
BOND-
ING.
See
BONDING.
BONDING
Bandwidth
On
Demand
Interoperability
Group.
A
set
of
protocols,
known
as
the
BONDING
specification,
developed
by
a
consortium
of
data
com-
munications
consultants
and

suppliers.
BONDING
arose
from
efforts
to
create
a standardized
inverse
multiplexing
protocol
in
order
to
improve
interoper-
ability
among
multiplexers
from
various
vendors.
The
BONDING
specification
describes
a
number
of
modes

ofinteroperability
for
switched
networks,
so
a
sideband
signal
can
be
subdivided
into
multiple
56
Kbps
or
64
Kbps
channels,
and
recombined
at
the
receiving
end.
bong A
tone
transmitted
through
a

phone
line
to
in-
dicate
to
the
listener
that
additional
information
is
required.
The
information
is
usually
entered
through
a
touchtone
key
pad
or
by
speaking
clearly.
Boole, George (1815-1864)
An
English-born

math-
ematician,
son
ofa
maid
and
a
shoemaker,
Boole
set
up
a
school
at
the
age
of
only
19.
He
taught
himself
mathematics
and
began
publishing
his
ideas,
intro-
ducing

Invariant
Theory.
His
t
854
publication
"The
Laws
of
Thought"
introduced
mathematical
concepts
applicable
to
computing
operations
and
earned
him
the
sobriquet
of"father of
symbolic
logic."
Boolean
logic
is
named
after

him.
Boolean expressionA
type
of
expression
often
used
in
programming
to
control
binary
relational
opera-
tions
that
may
be
executed
or
may
express
true
or
false.
Boolean
algebra
in
a
broader

sense
in
set
theory
involves
the
intersection
and
union
of
sets
and
ele-
ments
of
sets.
It
also
provides
a practical
means
for
implementing
logic
in
digital
computers.
Boolean
al-
gebra

works
readily
on
binary
computing
systems.
boom
1.
Vertical
spar,
beam,
pole,
or
suspended
pip-
ing.
2.
In
video,
a
vertical
bar,
rod,
or
other
support
for
microphones,
cameras,
or

other
equipment
that
need
to
be
suspended
over
or
near
a
source
with
a
minimum
of
visual
obstruction.
3.
The
horizontal
sup-
porting
rods
for
many
common
antennas
from
which

there
may
be
secondary
protruberances
to
increase
transmission
or
reception.
boom pole A
long
pole
with
a
spike
on
the
end
used
by
crews
of
boomers
(telephone
line
installers)
to
guide
a

long
telephone
pole
into
a
deep
hole.
A
boom
pole
is
sometimes
called
a
pike
pole.
boom truck roller
See
stringing
roller.
boomer
colloq.
Telephone
line
installer.
The
name
is
derived
from

the
boom
poles
installers
used
to
hand
guide
telephone
poles
into
their
holes
before
machin-
ery
for
this
job
became
prevalent.
boot
abbrev.,
v.
To
start,
to
power
up,
to

get
a
ma-
chine
going,
to
'kick'
something
into
operation.
De-
rived
from
bootstrap,
which
is
further
derived
from
the
phrase
"pulling yourself
up
by
your
bootstraps."
This
term
aptly describes
how

a computer
has
to
launch
its
basic
lower
processes
so
it
can
recognize
its
own
hardware
and
capabilities
in
order
to
further
launch
the
higher
level
processes.
See
bootstrap.
bootROMA
read-only

computer
memory
chip
usu-
ally
located
on
the
motherboard
as
an
essential
part
ofa
basic
system.
This
chip
provides
the
minimum
necessary information
for
bringing
the
computer
hardware
online
and
may

include
diagnostic
routines
that
test
systems
before
bringing
the
whole
system
up.
In
simple
terminals,
the
boot
ROM
may
include
all
basic
operating
software
needed
or,
as
is
the
case

on
most
self-contained
desktop
systems,
it
may
include
only
the
essentials
and
will
seek
a
floppy
diskette,
hard
drive,
or
other
boot
information
for
further
in-
structions
and
parameters
for

launching
the
operat-
ing
system,
device
drivers,
and
sometimes
user
ap-
plications.
On
many
Intel-based
desktop
computers,
the
infor-
mation
for
accessing
devices
may
be
transferred
to
the
BIOS
during

system
startup.
See
BIOS.
BOOTP
See
Bootstrap
Protocol.
bootstrap
In
a
computing
system,
to
bring
up
basic
hardware
and
software
systems
in
stages
that
are
par-
tially
or
wholly
dependent

upon
the
success
of
pre-
vious
stages.
For
example,
to
bootstrap
a
computer
from
apower-off
state,
low-level
hardware
and
soft-
ware
systems
are
brought
online
to
the
point
where
self

tests
can
be
performed
and
devices
recognized.
127
© 2003 by CRC Press LLC
Fiber
Optics
Illustrated
Dictionary
These
basic
systems
are
then
used
to
"pull
the
sys-
tem
up
by
its
bootstraps"
to
the

next
level
of
operat-
ing
system
capabilities
for
processing
input
from
the
user,
network
configurations,
and
basic
applications
parameters.
Bringing a
system
online
from
a power-off
state
is
called a cold
boot.
A
warm

boot
is
a
reset
from
a
power-on
state
during
which
the
system
typically
re-
reads
the
boot
ROM
and
restores
basic
operating
pa-
rameters without powering off
the
system
or
rerun-
ning
the

low-level
self-tests
and
device
intitialization
operations.
Stable
operating
systems
rarely
crash
or
hang,
but
there
are
some
microcomputer operating
systems
that
do
crash,
and
a
cold
boot
is
sometimes
the
only

way
to
bring
the
system
back
into
full
oper-
ating
mode.
See
device
drivers.
Bootstrap
Protocol
BOOTP.
An Internet Protocol!
User
Datagram
Protocol
(IPfUDP)
client/server
pro-
tocol
for
storing
and
providing configuration
infor-

mation
for
a
network.
BOOTP
evolved
in
the
ARPANET
days
to
enable
diskless client machines
and
other machines that
might
not
know
their
own
Internet addresses
to
dis-
cover
the
IP
address,
the
address
ofaserver

host,
and
the
name
ofa
file
to
be
loaded
into
memory
and
ex-
ecuted.
It
is
accomplished
in
two
phases:
address
de-
termination
and
bootfile
selection;
and
file
transfer,
typi-

cally
with
TFTP.
BOOTP
has
since
evolved
into
Dynamic
Host
Con-
figuration
Protocol
(DHCP).
See
Address
Resolution
Protocol,
Dynamic
Host
Configuration
Protocol,
Re-
verse
Address
Resolution Protocol,
RFC
951.
BOP
1.

beginning
of
packet.
2.
See
Biocomputing
Office
Protocol.
3.
See
bit-oriented protocol.
bopper A Biocomputing Office Protocol (BOP)
server
developed
by
Don
Gilbert,
based
on
popper, a
Post Office Protocol server. Bopper provides
biocomputing
services
to
BOP-compatible clients.
It
was
initially
released
for

Solaris2
in
June
1996.
Border Gateway Protocol
BGP.
An
interdomain
gateway
routing
protocol
which
is
superseding
Ex-
terior
Gateway
Protocol
(EGP).
BGP
is
used
on
the
Internet.
See
Exterior
Gateway
Protocol,
RFC

1163,
RFC
1267,
RFC
1268.
Border
Gateway
Protocol
Version
4
BGP4.
A
ver-
sion
ofBGP
which
uses
route
aggregation
to
reduce
the
size
of
routing
tables,
and
which
supports
Class-

less
Inter-Domain
Routing
(CIDR).
border
node
In
ATM
networking,
a logical
node
in
a specified
peer
group
that
has
at
least
one
link
that
crosses
the
peer
group
boundary.
Border
Node
A

means
for
establishing connections
between
networks
ofdistinct
topologies
while
limit-
ing
the
flow
of
topology data across subnetwork
boundaries.
Thus,
subnets
with
different
NETIDs
or
defined
clusters will
have
subnetwork boundaries.
Border
Node
was
defined originally
as

Peripheral
Border
Node
(PBN)
with
a later release
as
Extended
Border
Node
(EBN),
described
in
1997
by
Interna-
tional
Business
Machines
(IBM)
for
Advanced
Peer-
to-Peer
Networks
(APPNs).
EBN
was
developed
to

enable
connectivity of
mul-
128
tip
Ie
subnets.
It
facilitates interoperability,
topology
isolation, subnet partitioning,
route
calculation,
op-
tional
security,
optional
exit
access
controls,
and
other
functions.
Interior Border
Node
(IBN)
and
HPR
border
node

(HBN)
are
subsets ofEBN.
IBN
supports
intermedi-
ate
network
routing, usually
on
the
same
APPN,
but
does not support APPN Interchange Node or
SSE(CP)
functions.
HBN
supports
cross
subnet path
switching,
ANR
routing,
and
end-to-end
routing.
BORSCHT
An
acronym

used
in
the
telephone
in-
dustry
to
aid
in
remembering
the
components of a
subscriber
line
interface
(SLI).
B - battery (power source)
o-overvoltage protection
R-
ringing
S- signaling
and
signaling detection
C -
co
dec
(analog/digital conversions)
H-
hybrid
(two-/four-wire conversions)

T -
test
access.
Boston
Computer
Society
BCS.
Formally,
one
of
the
largest computer user groups
in
the world, with a
membership ofover 25,000
at
its
peak,
the
Society
served
users ofa variety of
types
ofcomputer plat-
forms.
Jonathan Rotenberg,
who
was
13
at

the
time
it
was
founded, ca.
1977,
is
credited
with
starting
the
organization. Despite a large
and
enthusiastic
membership,
the
Society officially
ceased
to
operate
in
September
1996.
bot,
'bot A
term
frequently
used
on
the

Internet
to
describe
software
robots
that
manage
tasks
on
behalf
of
users
and
operators, especially
in
Internet Relay
Chat
(IRC)
channels.
Since
IRC
is
an
interactive
so-
cial medium, these software programs have fre-
quently
been
given
personalities

by
their respective
programmers
and
thus
take
on
anthropomorphic
char-
acteristics
not
usually attributed
to
applications
pro-
grams,
hence
the
term
bot
instead
ofapplication.
See
avatar,
robot.
bottleneck Apoint
in
a
system,
device,

or
transmis-
sion
link
that
slows
the
rate of communication
be-
low
the
expected efficiency
or
below
the
capabilities
of
other
links
in
the
system.
For
example,
acomputer
with
a
CPU
capable of64-bit processing
may

be
im-
peded
by
a
32-
or
16-bit
data
bus.
As
another
example,
you
may
have
a
fast
serial
card
and
an
ISP
with
a Tl
line,
but
your
9600
baud

modem
creates
a
bottleneck,
limiting
the
upper
speed
of
the
transmission of
data.
Bottlenecks
may
be
aconstant limitation ofa
system
or
may
be
a limitation occurring
only
during
times
ofpeak traffic.
Bouguer,
Pierre (1698-1758) A
French
mathemati-
cian,

inventor,
and
author,
Bouguer carried
out
mea-
surements
in
astronomical photometry
in
the
1720s.
Beginning
in
1727,
he
was
a multiple winner of
the
grand
prize
of
the
Academie
Royale
des
Sciences.
In
1748,
he

invented photometric
and
heliophotometric
instruments.
Bouguer's significant
1729
essay
on
optics
describes
the
relationahip between
the
absorption of radiant
energy
and
the
associated absorbing
medium,
now
© 2003 by CRC Press LLC
known
as
Bouguer's
law.
Traite
d'Optique sur
La
Gradation
de

La
Lumiere,
his
treatise
on
photometry,
was
posthumously
published
as
a
first
edition
in
1760.
In
addition
to
his
observations
of
absorption proper-
ties of radiant energy
in
atmospheric optics,
it
de-
scribes a
number
oftypes ofphotometers, including

a
method
ofgoniophotometry.
See
Bouguer's
law.
Bouguer's lawAdescription
of
the
relationship be-
tween
an
absorbing
medium
and
the
radiant energy
absorbed
in
terms
of
the
ratio
of
the
transmitted
and
incident radiant energy intensity
to
the

mass
of
the
absorbing
medium.
Bouguer studied illumination
on
two
surfaces
from
light
sources
of
the
same
kind.
One
was
set
at
a
fixed
distance
from
the
illuminated surface but
had
an
ab-
sorptive

material
interposed between
the
light
source
and
the
illuminated surface,
the
other
was
set
up
the
same
way,
but
without
the
absorptive materials
and
with
the
light
source
set
at
varying distances
from
the

illuminated
surface.
The
intensity
of
the
illumination
on
the
first surface would vary depending
upon
the
thickness of
the
intervening materials
and
the
inten-
sity of
the
illumination
on
the
second
would
vary
ac-
cording
to
distance.

By
visually assessing
the
inten-
sity of
the
two
illuminated surfaces
as
the
thickness
or distance variables were altered and matched,
Bouguer
found
that
the
relationships between
the
two
could
be
perceived
and
quanitified. It's
not
a long
stretch
to
realize that
the

intervening materials could
also
be
swapped
and
the
experiment performed
again
for
a material ofdifferent composition (e.g., differ-
ent
translucency).
In
contemporary applications
of
the
concept,
the
re-
lationship
is
usually calculated
with
respect
to
a
spe-
cific wavelength with temperature
and
pressure held

constant.
It
provides
information
on
absorbancy
char-
acteristics or, seen another way, transparency.
Bouguer's
law
is
also
known
as
Beer's
law
or,
when
the
concepts
ofabsorption
in
proportion
to
aconcen-
trate
and
the
thickness
of

the
intervening materials
are
combined,
it
is
called Beer-Lambert's
law.
See
Lambert's
law.
boule
In
fiber
optics
fabrication,
a
sooty,
layered
coat-
ing
that
builds
up
inside a supporting
tube
through a
chemical deposition process.
The
boule

is
then
fur-
ther sintered
to
remove
impurities
and
collapse
the
boule into a clear cylinder preform. The preform,
which
is
typically composed
of
silica glass,
can
then
be
drawn
out
into
a
long
fiber
filament.
See
preform,
vapor
deposition.

bounce
1.
To
rebound,
to
come
back,
to
deflect off
of,
to
echo.
The
ionosphere
is
used
to
bounce radio
signals
over
long
distances.
2.
Inelectronic transmis-
sions,
if
data
doesn't reach
its
intended destination

and
is
routed back
to
the
sender,
it
is
said
to
have
"bounced."
This
may
happen
when
email
is
sent
to
an
address
that
no
longer exists,
for
example.
bounce, broadcast
1.
In

broadcast transmissions,
if
a signal
hits
a physical impediment,
it
may
bounce,
sometimes
causing
a
zone
in
which
there
is
interfer-
ence
in
the
transmission or
no
transmission
at
all.
In
other instances,
the
physical characteristics
of

the
Earth
and
the
ionosphere
and
the
position ofrepeat-
ers
or
satellites
may
be
used
to
selectively bounce a
signal
in
order
to
direct
it.
See
ionosphere,
Moon
bounce.
2.
In
visual media
such

as
television broad-
cast displays, bounce
is
an
undesirable
and
unex-
pected variation
in
the
brightness
of
the
image.
BOURBON Broadband Urban Rural Based Open
Networks.
An
ACTS
Project building
on
aprevious
RACE
project
which
studies
issues
of
providing
cost-

effective, scalable
access
to
ATM
-based networking
services
in
Europe
and
the
broader Information
So-
ciety.
The
project
focuses
both
on
users
and
technolo-
gies
and
involves
the
cooperation
of
Member
States
of

the
European
Union.
ATM
and
ISDN
test
beds
are
established in several countries. See BBL,
BONAPARTE,
BROADBANDLOOP,
UPGRADE,
WOTAN.
Bourseul,
Charles
(1829-1912) A Belgian-born
French researcher
who
described, but apparently
never followed
up,
a
means
of
transmitting speech
electrically through
wires.
His
ideas were published

in
L'Illustration
de
Paris
in
1854.
See
Meucci,
An-
tonio;
Gauthey,
Dom;
telephone
history.
Bower-BarffprocessAprocess
in
which
metal
(iron
or steel)
is
heated
to
red heat
and
then treated with
superheated steam
in
order
to

reduce vulnerability
to
corrosion.
Boyle, Robert (1627-1691) ABritish physicist
and
chemist
who
developed
pumps
that could
create
near
vacuums.
Boyle subsequently observed
that
sound
required a medium
for
its transmission.
He
also
did
numerous experiments
on
atmospheric pressure
and
discovered
an
important
relationship

between
gas
and
pressure
in
1662.
In
1675,
he
published a treatise
on
electricity
and
observed that the attractive properties
of
amber
did
not
require
the
presence
of
air.
Boyle's
law
is
named
after
him.
See

barometer; Boyle's
law;
Hauksbee, Francis.
Boyle's law, Marriotte's law
At
aconstant
tempera-
ture,
the
volume
ofa definite
mass
of
gas
is
inversely
proportional
to
the
pressure such that
the
product of
the
volume
(PV)
is
constant.
BP
1.
bandpass.

2.
base
pointer.
3.
beam position.
4.
bypass.
BPAD
Bisynchronous Packet AssemblerIDisassem-
bIer.
The
BPAD
Protocol
is
a transport protocol
as-
sociated with
X.25
networking.
BPDU
See
Bridge Protocol Data
Unit.
BPI
See
bytes per
inch.
BPON
See
Broadband Passive Optical

Network.
BPM
See
beam
position
monitor.
BPS
See
bits per
second.
BPSK
See
binary phase-shift
keying.
BR
1.
beacon
receiver.
2.
Bureau
of
Radiocommu-
nications.
Bragg angle
In
the
context
of
Bragg's
law,

the
angle
between the lattice plane and the incident X-ray
beams (commonly expressed
as
theta - 8). See
Bragg's
law.
Bragg reflector A technology used
in
diode
lasers
that allows very
fine
control over
the
focus
of
the
beam. A Bragg reflector
is
also called a grating
129
'
Yi0t
ll!
.
~,:,,',:~:f,:
I
!!t~~:

•
© 2003 by CRC Press LLC
Fiber
Optics
Illustrated
Dictionary
reflector,
due
to
the
corrugated
ridges
used
to
direct
the
beam
that
change
along
their
lengths.
Bragg
re-
flectors
are
being
researched
as
a

means
of
increas-
ing
throughput
of
data
transmissions
in
existing
cable
installations.
By
finer
focusing
of
the
beams
and
mul-
tiplexing,
capacity
may
be
improved
on
fiber
chan-
nels.
See

Agility
Communications,
Bragg
grating,
diffraction,
quantum
cascade
laser.
Bragg grating A
grate-like
pattern
that
is
"written"
into
a
fiber
during
fabrication
to
modify
the
charac-
teristics
of
the
basic
fiber
filament
to

reflect
wave-
lengths
selectively.
The
performance
of
the
grating
may
also
be
improved
by
straining
the
fiber
medium
at
the
time
the
grating
is
written.
Bragg
gratings
have
provided
significant

advance-
ments
in
waveguide
control
in
fiber
optics
commu-
nications
circuits.
There
are
many
types
of
grating
design
(and
research
continues)
that
enable
the
reduc-
tion
of
noise
and
delay,

through
filtering
mechanisms
that
may
be
tunable
and
incorporated
into
optical
waveguides.
Gratings
can
facilitate
channel
filtering
and
gain
equalization.
Research
at
the
MIT
N
anoStructures
Laboratory
has
resulted
in

new
Bragg
grating
designs
and
fabrica-
tion
techniques
for
lithographically "etching"
the
grating
into
the
medium.
For
example,
the
lab
has
shown
that
a
quarter-wave
shift
in
the
grating,
to
iso-

late
a
single
wavelength
channel
in
a
multi
wavelength
system,
can
provide optical resonating functions,
similar
to
that
ofa
Fabry-Perot
cavity.
Thus,
add/drop
channel
filtering
capabilities
can
be
built
right
into
the
fiber

facilitating
the
development
of
all-optical
transmission
paths.
Through
electrical
circuit
mod-
eling,
multiple
resonators
can
be
cascaded
to
enable
more
complex
functions.
See
add/drop
multiplexer,
Alexandrite,
diffraction,
fiber
grating.
Bragg spectrometerA

form
of
spectrometer
useful
in
studying
X
-ray
diffraction characteristics
based
upon
the
discoveries
and
observations
of
W.H.
and
W.L.
Bragg
in
the
early
1900s.
X
-rays
are
generated,
filtered,
and

collimated
(aligned
into
a
fine
beam)
and
aimed
to
strike
a
crystal
surface
at
a
specified
angle.
The
rays
reflected
from
the
crystal
are
intercepted
by
a
detector
so
that

their
characteristics
may
be
stud-
ied
and
recorded.
See
Bragg's
law.
Bragg's law, Bragg's relation A
diffraction
effect
expressed mathematically
as
nl
= 2d sinq
by
W.
Lawrence
Bragg
in
1913
to
describe
the
angles
of
incidence associated with X-ray reflections that

occur
when
parallel
rays
encounter
crystal
structures
(
obstacles).
Thus,
the
wavelength
of
an
incident
beam
times
a
positive
integer
(sometimes
expressed
as
an
index
-
m)
is
equal
to

two
times
the
distance
between
the
atomic
layers
in
the
crystal
sinq.
Depending
upon
which
factors
are
known
and
substituted
into
the
equation,
diffraction
angle,
crystal
plane
separation,
or
the

wavelength
can
be
algebraically
calculated.
The
relational
expression
was
based
upon
collabora-
tive research with Lawrence Bragg's father,
W.H.
Bragg.
The
Braggs'
observations
were
signifi-
cant
not
only
for
their
practical
applications,
but
for
providing evidence supporting theories

about
the
130
periodic
atomic
structure
of
crystals.
Bragg's
law
and
the
study
of
diffraction
have
since
been
applied
to
many
other
theoretical
and
practical
fields
of
study
beyond
X

-rays
and
crystals.
See
Bragg
grating,
Bragg
reflector,
Compton
scattering.
Bragg,WilliamHenry
(1862-1942)
A
British
physi-
cist
who
studied
X-rays
and
ionizing
radiation
and,
in
collaboration
with
his
son,
X
-ray

diffraction
and
its
interaction
with
crystalline
lattice
structure.
This
latter
research
won
the
father/son
team
a
Nobel
Prize
in
physics,
in
1915.
See
Bragg
spectrometer.
Bragg,WilliamLawrence(1890-1871) An
Austra-
lian-born
British
physicist

who
studied
at
Cambridge
and
became
a
lecturer
there.
In
the
early
1900s
he
col-
laborated
with
his
father,
W.H.
Bragg,
in
the
study
of
X-ray
diffraction
and
crystal
structures,

an
effort
that
jointly
won
them
a
Nobel
Prize
in
physics
in
1915.
In
1915,
they
published X-rays and Crystal
Structure.
In 1938, Lawrence Bragg became head
of
the
Cavendish
Laboratory
at
Cambridge.
From
1953
to
1961,
he

served
as
director
of
the
London
Royal
In-
stitution.
braid A
fibrous
or
filamentous,
long,
tubular
intri-
cately
woven
structure
usually
of
plastic
or
fine
metal
that
forms
a
covering
over

a
conductive
or
insulat-
ing
core
in
a
layered
cable.
Brainerd, Paul
Brainerd
founded
Aldus
Corporation
in
1984,
the
year
after
the
introduction
of
the
Apple
Lisa
computer
and
the
year

before
the
release
of
the
Apple LaserWriter printer. Aldus specialized
in
graphics
applications,
particularly
for
vector
draw-
ing
and
desktop
publishing.
Macintosh
computers
and
Aldus
software
quickly
became
favorites
with
print
industry
service
bureaus.

The
Aldus
Corporation
was
one
of
the
few
developers
that
created
some
really
good,
quick,
intuitive
user
interfaces.
Good
interface
design
is
a
rare
talent
in
the
software
development
industry.

Aldus
PageMaker
and
Aldus
Freehand,
de-
veloped
by
the
Aldus
Corporation,
were
acquired
by
Adobe
Systems
and
Macromedia.
brainiac
Probably originating from Edmund
Berkeley's
computing
devices
from
the
1950s,
this
term
refers
to

someone
with
good
technical
and/or
mathematical
intelligence
of
the
kind
that
is
not
com-
mon.
See
Brainiac.
Brainiac Brain-Imitating,
Almost-Automatic
Com-
puter.1t
is
essentially
the
electromechanical
GENIAC
computer
designed
by
Edmund

C.
Berkeley
and
Ol-
iver
Garfield,
in
the
1950s.
There
were
disputes
and
a
lawsuit
between
Berkeley
and
Garfield
subsequent
to
which
Garfield
promoted
his
calculating
technol-
ogy
under
the

name
GENIAC,
and
Berkeley
contin-
ued
to
promote
computing
devices
under
the
name
Brainiac.
In
writings
on
the
GeniacIBrainiac
technol-
ogy,
Berkeley
described
Brainiac
computing
experi-
ments'
in
1957
and

1958,
and
began discussing
Brainiac's
relationship
to
GENIACs
and
automatic
computers,
in
1958.
In
the
late
1950s,
Berkeley
took
steps
towards
exporting
Brainiac
abroad,
as
well.
See
Berkeley,
Edmund;
GENIAC;
Simon.

branch
1.
Ajunction
point
from
which
there
is
more
© 2003 by CRC Press LLC
than
one
path
along
which
to
continue.
2.
An
instruc-
tion
in
a
computer
program
which,
when
evaluated,
can
lead

to
a
different
destination
for
execution
of
the
next
step,
depending
upon
the
condition.
3.
A
sub-
station,
subsidiary
office,
or
other facility
which
is
a
satellite
of,
or
auxiliary
to,

the
main
operations.
branch circuit
In
a wiring installation, a separate
circuit
that,
if
damaged
or
tripped,
doesn't
affect
the
other
branch
circuits.
This
divides
the
power
so
the
main
circuit
is
not
overloaded.
On

a circuit breaker
panel,
the
branch
circuit
is
a constellation of
appli-
ances
and
sockets
wired
to
a particular
breaker.
branch feeder
In
an
electrical distribution
system,
a
cable
that
connects
the
main
cable
and
the
subscriber

distribution
system,
as
between a
phone
switching
center's
main
cable
and
a
business
distribution
closet.
branch office
BO.
Subsidiary
office
(in
the
sense
that
a
tree
branch
is
subsidiary
to
a
tree

trunk)
separate
from
the
head
office.
There
may
be
multiple
branch
offices.
In
large distributed computer networks,
branch
offices
are
often
established
to
provide
rout-
ing
or
switching
services,
customer
services
(includ-
ing

installation,
maintenance,
and
repairs),
and
local
marketing,
billing,
and
tax
procedures.
branching
1.
Dividing, splitting
into
two
or
more
paths
or
sections.
2.
A hierarchical structure
often
used
for
database creation, search,
and
retrieval.
3.

Branching
electrical distribution
systems
for
elec-
trical
installations
and
data
networks.
branching filter
1.
A
device
for
separating
or
com-
bining
separate
frequencies
when
used
in
conjunc-
tion
with
a
guiding
structure

for
the
wave.
2.
In
com-
puter
networking,
a software utility
for
selectively
routing
data
into
several
paths
or
files
based
on
speci-
fied
characteristics.
BranlydetectorA
device
created
in
1890
by
Edouard

Branly,
consisting
ofa
small,
glass,
metal-filled
tube
with
a
short
wire
inserted
to
make
contact
with
the
metal filings.
When
connected between a power
source
and
a
meter,
current didn't
pass
through
the
glass
unless

a
spark
was
discharged.
The
spark
caused
the
filings
to
cohere
and
thus
act
as
a
conductor.
This
on/off
quality
of
the
Branly detector
was
very
useful
to
the
dev,elopment
of

radio.
Branly,
Edouard
Eugene Desire (1844-1940) A
French
inventor
who
devised
the
Branly detector
in
the
late
1800s,
a
cohering
device
that
contributed
to
the
development
of
radio
or,
as
it
was
then,
wireless

telegraphy.
His
technology
was
subsequently
adapted
by
G.
Marconi.
Branly
also
investigated
the
transmis-
sion
of
nerve
impulses.
See
Branly
detector,
coherer.
BRAS
broadband
remote
access
server.
Braun,KarlFerdinand (1850-1918)A
German
re-

searcher
who
discovered
in
the
1870s
that certain
minerals
had
a property of
one-way
conductivity of
radiant
energy;
they
could
function,
in
a
sense,
as
one-
way
gates.
This
discovery
was
an
important
early

con-
tribution
to
electronic
circuitry
that
provided a
tran-
sition
from
coherers
to
crystal
detectors.
Braun invented
the
cathode-ray indicator
tube
or
Braun
tube
in
1897,
a significant
device
in
the
evo-
lution
of

electronics.
Braun's
attitude
towards
science
was
similar
to
Benjamin
Franklin's.
While
Franklin
was
a
shrewd
and
successful
businessman,
he
also
had
a
strong
inclination
to
share
knowledge
that
he
felt

would
benefit
humankind.
Like
Franklin,
Braun
published
descriptions
of
his
earlier
discoveries
rather
~~~ek~;h~~~:e~:~~~~t~~~::~~~~r;;~~:n~r:J~r;
iB
tuning
transmitters
in
Britain, starting
in
1899,
tech-
nology
that
may
have
influenced Marconi's
tuning
patent of
1900.

Ayear
after
his
invention
of
the
CRT,
Braun
was
hired
to
provide
guidance
on
an
undetwater
wireless
tele-
graphy
project
that
needed
improvements.
By
rear-
ranging
the
main
components
of

the
circuits
and
al-
tering
the
coupling,
Braun
was
able
to
greatly
extend
the
range
of
the
system.
His
employer
and
backers
formed
the
Telebraun
company
which
evolved
into
the

well-known
Telefunken.
Braun
was
awarded
aN
obel
Prize
in
Physics
in
1909,
along
with
G.
Marconi,
for
his
contributions
to
wire-
less
telegraphy.
See
cathode-ray
tube;
crystal
detec-
tor;
Murgas,

Jose£
BRCS Business
and
Residence
Customer
Service.
breadboard
A board with numerous attachment
points,
often
in
a
grid,
that
permits
the
prototyping
of
circuits.
Breadboards
often
resemble
a
nest
of
col-
ored
worms,
as
they

are
frequently
hand-wired
with
a lot
of
crisscrossing conductors with temporary
attachments. Breadboards
are
handy
for
concept
de-
sign,
testing,
teaching,
temporary
circuits,
and
con-
vincing
the
boss
that
you
have
a
good
idea
that

will
work.
See
proofof
concept.
break
Willful
or
inadvertent
interrupting
or
stopping
ofa
process,
transmission,
or
broadcast.
On
computer
terminals,
a
break
can
be
sent
in
many
instances
with
Ctrl-C

or
Esc,
depending
upon
the
software.
break
in
1.
v.
Interrupt,
or
take
control
of,
a circuit
or
process.
This
break
may
be
from
human
or
sys-
tems
intervention
or
through

an
automated
system.
See
Barge
In,
buttinsky.
2.
lJ.
Gain
illegal
entry
to
a
system.
See
back
door,
hacking,
Trojan
horse.
Break
keyAspecialized
key
included
on
some
com-
puter
keyboards

that
permits
a
one-keystroke
inter-
ruption of
the
current
task,
assuming
the
software
supports,
and
correctly interprets,
the
input
from
the
keystroke.
Break
keys
are
included
since
some
of
the
common
ways

to
interrupt
tasks
involve
combination
keystrokes,
such
as
Ctrl-C,
and
hitting
one
key
is
easier,
especially
for
less
experienced
computer
us-
ers.
See
break.
break
out box
See
breakout
box.
breakdown potential, breakdown strength

Dielec-
tric
strength,
the
maximum
voltage
that
can
be
toler-
ated
without
breakdown.
breakdown voltage
1.
The
voltage
at
which
an
in-
sulator
or
dielectric
breaks,
or
at
which
ionization
and

conduction
occurs
in
a
gaseous
environment.
2.
The
voltage
that
needs
to
be
applied
in
a
device
to
jump a
gap
(in
air).
breaker
1.
In
electrical installations, a point
in
a
circuit, usually ajunction installed
in

series
between
the
main
electrical
source
and
a branch circuit,
in
131
© 2003 by CRC Press LLC