Fiber Optics Illustrated Dictionary - Part 13 pot

Fiber
Optics
Illustrated
Dictionary
While
the
invention
of
the
telephone
was
not
as
revo-
lutionary
as
the
telegraph
in
technical
terms,
it
was
a
highly
significant,
culture-changing
evolutionary
step
that
personalized

distance
communications
and
facili-
tated
commerce
in
ways
not
previously possible.
See
audiometer; Bell System; Berliner, Emil; Edison,
Thomas
Alva;
Gray,
Elisha;
Meucci,
Antonia; Reis,
Philip;
Photophone;
telephone
history.
Bell
asynchronous standards A
series
of
full
duplex
standards developed
by

AT&T.
These
were
widely
supported
by
other manufacturers
in
the
late
1970s
and
early-/mid-1980s. Other vendors
and
standards
bodies
began
competing
with
the
Bell
standards,
most
notably Hayes,
in
the
early 1980s. The V Series
Recommendations
by
the

ITU-T
are
now
the
domi-
nant
formats.
Some
Bell
standards
are
shown
in
the
Bell
Serial
Communications Standards
chart.
BelJ
Atlantic Aholding company created
as
a result
of
the
AT&T
divestiture
in
the
mid-1980s.
See

Bell
Operating
Company.
Bell
Canada,
Bell
Telephone Company ofCanada
The
Canadian
arm
of
the
Bell
system
until
the
1970s,
when
it
became
separated
from
the
U.S.
Bell
system.
Bell
Canada
was
a

member
of
the
Stentor Consor-
tium,
along
with
BC
Tel
Ltd.,
SaskTel,
and
others.
As
companies
merged
and
were
bought
out,
the
Sten-
tor
alliance dissolved
and
Bell became mainly
fo-
cused
on
the

provinces ofOntario
and
Quebec.
Bell
is
the
major
telecommunications carrier
and
supplier
of
telecommunications equipment
in
Canada.
Through mergers, BCT.TELUS Communications
Inc.
became
the
second
largest telecommunications
company
in
Canada.
In
1997,
Bell
Canada
and
TELUS
Cable Holdings

Inc.
both
applied
to
the
CRTC
for
broadcast distri-
bution
licenses
to
conduct trials
of
broadcasting
ser-
vices,
while distributing telecommunications
services
over
the
same
digital networks.
In
1999,
both
Bell
and
TELUS
testified
on

issues of promoting elec-
tronic
commerce
by
protecting personal information
related
to
Bill
C-54.
Bell Canada Relay Service
BCRS.
A 24-hour
ser-
vice
that
allows
TTY
users,
who
may
be
hearing
im-
paired,
to
talk
to
one
another
or

to
a hearing person
with
the
help
ofspecially trained operators translat-
ing
through
teletypewriter terminals.
The
TTY
equip-
ment
can
signal
up
to
60
words
per minute.
As
an
example
of
the
service,
the
subscriber calls
the
BCRS

operator
and
provides
his
or
her
name
and
number
and
the
number of
the
person
to
be
called.
The
operator requests billing information
and
then
places
the
call.
The
operator
then
acts
as
a translator,

conveying a text message
by
voice
to
the
hearing
callee,
and
a voice
message
by
text
to
the
hearing-
impaired
caller.
The
call
is
kept
confidential
by
the
operator,
and
no
record
of
the

conversation
is
retained.
BCRS
services
are
billed
at
the
same
rate
as
normal
phone
charges.
Bell
Communications Research Bellcore. An
orga-
nization established
as
a result of
the
AT&T
divesti-
ture
to
provide a variety
of
central administration,
training, standards, documentation,

and
quality
ser-
vices
to
the regional Bell companies
who
fund
Bellcore
and
their subsidiaries.
It
is
roughly equiva-
lent
to
the
Central Services portion of
the
pre-dives-
titure
AT
&T
organization.
Bell
Laboratories,
Bell
Telephone Laboratory,
Bell
Labs

The
research
arm
of
the
Bell
system
responsible
Bell Serial Communications
Standards
Standard Speed
Notes
Bell
103
300
Asynchronous
full
duplex
communications standard
for
transmitting
at
speeds
up
to
300
bps
over
publicly
switched

telephone
networks
(PSTNs).
This
standard
was
commonly
used
with
computer
modems
in
the
late
1970s,
but
was
superseded
by
Bell
212
in
the
early
1980s.
Bell
212
1200
An
AT&T

asynchronous
full
duplex
communications
standard
for
transmitting
at
speeds
up
to
1200
bps
over
publicly
switched
telephone
networks
(PSTNs).
This
standard
was
commonly
used
with
computer
modems
in
the
early

1980s,
but
was
superseded
by
Bell
20
I
in
the
mid-1980s.
Bell
201
2400
Asynchronous
full
duplex
conmmnicalions
standard
for
transmitting
at
speeds
up
to
2400
bps
over
publicly
switched

telephone
networks
(PSTNs).
This
standard
was
commonly
used
with
computer
modems
in
the
mid-1980s.
Many
other
vendors
began
entering
the
modem
manufacturing/standards
industry
at
this
time.
Bell
208
4800
Asynchronous

full
duplex
communications
standard
for
transmitting
at
speeds
up
to
4800
bps
over
publicly
switched
telephone
networks
(PSTNs).
This
standard
did
not
particularly
catch
on
in
consumer
markets.
Many
users

leapfrogged
from
2400
bps
to
9600
bps
as
vendor
participation
and
competition
for
faster
speeds
increased
in
the
mid-1980s.
112
© 2003 by CRC Press LLC
for
many
important
discoveries
and
the
development
of
thousands

of
telecommunications
technologies
and
devices
over
the
decades.
The
labs
were
established
as
a
combined
effort
of
the
Western
Electric
Com-
pany
and
the
AT&T
engineering
departments
in
1907.
It

grew
to
be
the
largest
industrial
research
organiza-
tion
in
the
U.S.,
and,
in
1925,
the
engineering
depart-
ment
of
Western
Electric
was
incorporated
as
Bell
Laboratories,
with
the
head

office
in
New
York
City.
In
1941,
headquarters
were
moved
to
Murray
Hill,
New
Jersey
and
larger
plants
were
later
established
in
Denver
and
Atlanta.
Smaller
field
stations
and
sat-

ellite
labs
were
regularly
established
over
the
years
in
many
parts
of
the
U.S.
In
1934,
AT&T's
research
division
was
merged
into
Bell
Laboratories.
Bell LabsMuseumAn
online
resource
sponsored
by
Lucent

Technologies.
You
can
visit
the
images
and
historical
references
at
the
Bell
Labs
Museum
Web
site.
/>Bell Operating Company
BOC.
This
is
defined
in
the
Telecommunications
Act
of
1996
and
published
by

the
Federal
Communications
Commission
(FCC),
as
"

any
of
the
following
companies:
Bell
Telephone
Company
of
Nevada,
Illinois
Bell
Telephone
Com-
pany,
Indiana
Bell
Telephone
Company,
Incorpo-
rated,
Michigan

Bell Telephone
Company,
New
England
Telephone
and
Telegraph
Company,
New
Jersey
Bell
Telephone
Company,
New
York
Tele-
phone
Company,
U S
West
Communications
Com-
pany,
South Central Bell Telephone Company,
Southern
Bell
Telephone
and
Telegraph
Company,

Southwestern
Bell
Telephone
Company,
The
Bell
Telephone
Company
of
Pennsylvania,
The
Chesa-
peake
and
Potomac Telephone Company, The
Chesapeake
and
Potomac
Telephone
Company
of
Maryland,
The
Chesapeake
and
Potomac
Telephone
Company
ofVrrginia,
The

Chesapeake
and
Potomac
Telephone
Company
of
West
Vrrginia,
The
Diamond
State
Telephone
Company,
The
Ohio
Bell
Telephone
Company,
The
Pacific
Telephone
and
Telegraph
Company,
or
Wisconsin
Telephone
Company;
and
(B)

includes
any
successor
or
assign of
any
such
company
that
provides
wireline
tele-
phone
exchange
service;
but
(C)
does
not
include
an
affiliate of
any
such
company,
other
than
an
affiliate
described

in
subparagraph
(A)
or
(B)."
See
Federal
Communications
Commission,
Telecom-
munications
Act
of
1996.
Bell speak
colloq.
A
phrase
to
describe
the
substan-
tial
body
of
telephone
jargon
that
grew
up

over
the
decades
within
the
Bell
system,
particularly
among
technicians
and
scientific
researchers.
Bell System
The
original
holders
of
the
Bell
tele-
phone
patents
formed
by
Bell,
Sanders,
and
Hubbard
in

1877,
and
incorporated
in
1878,
less
than
15
years
after
the
invention
of
the
telephone.
The
company
thrived
and
grew
under
the
management
of
Theodore
N.
Vail.
Since
the
term

of
exclusivity
granted
by
a
patent
lasted
only
17
years,
the
expiry
of
the
Bell
pat-
ents
resulted
in
the
founding
of
thousands
of
new
in-
dependent
phone
companies.
These

gradually
were
merged
and
consolidated
into
the
Bell
System.
In a
1984
court decision, divestiture of
the
American
Telephone
and
Telegraph
company
(AT&T)
removed
the
distinction
between
the
Bell
company
and
inde-
pendent
phone

companies.
Bell Telephone Company
of
Canada
Inc.
Estab-
lished
in
1880,
Bell
Canada
began
by
providing
ser-
vice
to
the
larger
centers
in
eastern
Canada,
most
of
which
were
interconnected within
about
10

years.
Bell
Canada
is
under
the
jurisdiction of
the
Canadian
Radio
Television
and
Telecommunications
Commis-
sion
(CRTC).
Bell Telephonic Exchange
The
first
telephone
ex-
change
in
Ohio
State.
Bellcore
See
Bell
Communications
Research.

BellinghamAntique RadioMuseum
See
American
Radio
Museum.
BellSouth
Corporation
A
large
regional holding
company
created
as
aresult of
the
AT&T
divestiture
in
the
mid-1980s.
It
is
comprised
of
Southern
Bell
Telephone
and
South
Central

Bell
Telephone
Com-
pany
and
a
number
of
other
companies.
BellSouth
is
cooperating
with
Nippon
Telegraph
and
Telephone
to
provide
large-scale
integration of
residential
fiber
multimedia
telecommunications
services.
See
Bell
Operating

Company,
fiber
to
the
home.
benchmark
1.
A
specified
expression
of
performance
based
on
agreed-upon
test
criteria.
2.
A
criterion
ex-
pression,
often
numeric,
against
which
other
systems
or
processes

are
compared.
Benchmarks
are
so
sys-
tem
specific
that
it
is
hard
to
translate
benchmark
per-
formance
scores
to
real-life
computing
situations,
and
their
validity
is
often
hotly
contested.
See

benchmark
test.
benchmark test A
criterion
test
for
evaluating
the
performance
ofa
system,
often
applied
to
the
speed
of processing. Although benchmark
tests
may
be
straightforward
for
simple
electronic
components,
they
are
sometimes
used
to

evaluate
the
system
per-
formance
of
complex
systems,
which
is
difficult
to
measure
in
objective
units.
For
example,
a
computer
with
a
40-MHz
CPU
will
perform
more
slowly
on
benchmark

tests
than
a
200
MHz
RISC
chip
CPU,
yet
a
word
processor
running
on
one
system
may
have
the
same
apparent
speed
to
the
user
as
one
running
on
a

faster
system
due
to
many
factors
such
as
load
on
the
system,
user
interaction,
software
optimiza-
tion,
address
bus
bottlenecks,
amount
and
type
of
memory,
etc.
In a
broad
sense,
benchmarks

cannot
be
said
to
provide
definitive
performance
measures,
but
they
are
nevertheless
often
established
as
abest-
efforts
way
of comparing
and
contrasting
systems
with
significantly
different
construction
and
charac-
teristics.
Even

these
are
often
considered
"better
than
nothing" performance indicators.
See
Dhrystone,
Rhealstone,
Whetstone.
bend loss In
cabling,
attenuation
caused
by
bends
and
twists
in
the
wires
or
fibers.
At
each
bend
there
is
a

tendency,
especially
in
optical
fibers,
for
the
signal
to
want
to
continue
to
radiate
in
the
same
direction,
113
© 2003 by CRC Press LLC
Fiber
Optics
Illustrated
Dictionary
resulting
in
slight
losses through
the
cladding

as
the
cable
curves.
See
Bend
Factors
diagram.
bend
radius
In
cabling
and
cabling enclosures, a
description
of
the
bend
tolerance
ofa
certain
material
at
a
certain
radius,
often
under
a
certain

pulling
force.
This
measure
is
important
for
manufacturing,
for
se-
lecting
types
and
sizes
of
parts,
and
for
installing
pul-
leys,
cables,
and
wires.
See
bend
loss.
bend-insensitive
fiber
Fiber

optic
cable
that
is
par-
ticularly resistant
to
losses
when
the
fiber
is
bent.
Bend-insensitive
fibers
were
first being developed
and
described
in
the
late
1980s.
There
are
various
ways
to
reduce bend-induced
loss

in
optical
fibers.
The
materials,
diameter
and
ratio
of
core
to
cladding,
and
the
numerical
aperture
can
all
influence sensitivity
to
bend
losses.
For
example,
in-
creasing
the
numerical
aperture
(e.g.,

NA
=
0.16
for
single-mode
fiber)
can
confine
the
reflected light
more
tightly
within
the
conducting
core,
producing
a
more
bend-insensitive
fiber.
Benedicks,
Manson
An
American
researcher
who
investigated
the
electromagnetic-influencing

proper-
ties
of
germanium
crystals
in
the
early
1900s
and
found
that
they
could
be
used
to
convert alternating
current
(AC)
to
direct
current
(DC).
Benjamin
Franklin
Institute
of
Global Education
A resource

and
Web
center that supports
and
pro-
motes
affordable
access
to
education
from
global
re-
sources
through
distance
education,
founded
in
the
mid-1990s
by
John
Hibbs.
l
bent
pipe
A description
for
a communications

con-
duit,
path,
or
transmissions
medium
that reflects
an
incoming
signal
at
an
angle,
usually between
20
and
70
degrees,
thus
following a path that resembles a
bent
pipe.
This
is
a
very
common
configuration
for
Earth-satellite/satellite-Earth transmissions

and
for
radio
transmissions which
are
channeled
by
being
bounced
off
the
ionosphere.
Benton
Foundation An organization established
in
1948
that
has
promoted diverse
and
equitable public
use
of communications technologies
for
its
social
benefits since
1981.
It
is

named after its founder,
William Benton (1900-1973), a U.S. Senator,
UNESCO
Ambassador,
and
publisher of
the
Ency-
clopedia
Britannica.
The
Benton
Foundation
provides
news
on
communications policy
and
the
social
use
of technologies;
it
supports a
number
of
free
online
newsletters
and

discussion
lists.
The
Foundation
op-
erates
from
an
endowment along with additional
funding
from
major communications industry
ven-
dors
and
philanthropical organizations.
See
Commu-
nications Policy Project.
BeDS
An
object-oriented, multitasking, fast,
non
legacy,
microcomputer operating
system
devel-
oped
by
Be,

Inc.,
under
the
leadership ofJean-Louis
Gassee.
Programmers claim
it
is
a pleasure
to
pro-
gram
and
that
the
environment
is
powerful
and
yet
easier
to
learn
and
use
than
many
others.
Bend Factors
in

Fiber Optic Lightguides
Light
is
guided thlVugh a fiber
optiC
cable thlVugh a process called total internal reflection (TIR) in which the
outer cladding. which has a different refi'active indexfi'om the inlier conducting core
(in
this case, a multimodefibel),
reflects the light beam back into the core. This plVcess continues even
if
thefiber
is
bent
to
some extent, which is very
useful
for
network cable installation alldfiber optic plVbes
for
scielltific
or
medical purposes. However, there are
limits
to
how much a cable call be bent without bend-induced loss
of
signal.
In
the diagram above, the amount

of
loss
ill
the bend depends upon the bend radius, the relationship
of
the core to
the claddillg
in
tenns
of
size andrefractive index, and the allgle at which the beams encounter the cladding.
If
a light
beam
(A)
passes the maximum point
of
bend, it may continue on thlVugh the lightguide. In contrast, a beam
(B)
traveling at a different angle such that it hits the cladding at the bend, beyond the critical angle at which it,can be
reflected backinto thefiber, wouldbepartly absorbed by the cladding and by any materials outside the cladding and
would be lost as
far
as the fiber core is concerned. Commercial mamifacturers design certain cables to minimize
bend loss, by balancing cable parameters. Thus, bend-insensitive cables often have a higher numerical aperture.
114
© 2003 by CRC Press LLC
Gassee
is
well

known
for
his
previous
contributions
to
R&D
at
Apple
Computer,
when
the
Apple
II
line
was
being
developed.
BeDS
is
aimed
at
multimedia
audio
and
visual
applications.
BeDS
was
introduced

to
developers
late
in
1995
along
with
the
Be
computer.
About
a
year
later,
Be,
Inc.
dis-
continued
the
hardware,
to
concentrate
on
software
development,
as
their
operating
system
software

is
able
to
run
on
several
hardware
platforms
by
various
vendors.
See
Be,
Inc.
BEP
1.
See
back end processor.
2.
Bureau
Economique
de
la
Province
de
Namur.
3.
Bureau
of
Engraving

and
Printing
(Federal)
4.
Business
Enterprise
Program
(for
minorities
and
handicapped
workers).
BER
1.
See
Basic
Encoding
Rules.
2.
See
bit
error
rate.
Berkeley, Edmund Callis (1909-1988)
An
Ameri-
can
educator
and
pioneer

computer
developer
who
worked
on
the
Mark
II
construction
project
in
1942
and
developed
a
lifelong
interest
in
computer
appli-
cations.
Berkeley
founded
the
Eastern
Association
for
Computing
Machinery
in

1947,
which
became
the
respected Association
for
Computing Machinery
(ACM)
the
following
year.
In
1948,
Berkeley
started
his
own
company,
Berke-
ley
Associates,
to
market
his
inventions.
He
authored
many
books
foreshadowing

computer
and
telecom-
munications
history.
In
1949,
Great
Brains,
Or,
Ma-
chines
That
Think
was
released
with
instructions
on
how
to
design
computing
devices.
In
1950,
Berke-
ley
published
Computers

and
Automation,
a
historic
computing
magazine.
In
1956,
he
coauthored
Com-
puters,
Their
Operation and Applications with
L.
Wainwright.
And,
in
1959,
he
authored Symbolic
Logic
and
Intelligent
Machines.
Following
up
on
the
ideas

in
Great
Brains,
Berkeley
described
and
constructed
one
of
the
first
desktop
mi-
crocomputers
that
became
generally
known
through
popular publications. The Simon (named after
"Simple
Simon")
was
made
public
in
an
electronics
magazine
in

1950
(as
construction
plans).
Berkeley
was
also
actively
interested
in
the
design
and
con-
struction
of
small
robots
(quite
prolific,
in
fact),
which
he
marketed through Berkeley Enterprises, Inc.
(originally
Berkeley
Associates).
Berkeley
sought

to
bring
computing
concepts
to
hob-
byists
through
the
GENIAC
computing
device.
Un-
fortunately,
after
disputes
with
his
business
partners,
Berkeley
lost
the
legal
right
to
use
the
name,
so

he
gave
the
name
Brainiac
to
essentially
the
same
tech-
nology
and
his
former business partner used
the
Geniac
name
to
market
tube-shaped
calculators.
The
archival
legacy
of
Edmund
Berkeley
from
1923
to

1988
has
been
donated
to
the
Charles
Babbage
in-
stitute
by
Berkeley
Enterprises,
Inc.
and
the
Berke-
ley
family.
See
Brainiac,
Charles
Babbage
Institute,
GENIAC,
Simon.
Berkeley Internet Name Domain
BIND.
A
popu-

lar
implementation
of
the
Internet
domain
name
ser-
vice
(DNS)
originally
developed
and
distributed
by
the
University
of
California
in
Berkeley.
There
have
been
numerous commercial implementations of
BIND.
As
of2001,
BIND
4.9.8

(for
older
systems),
BIND
8.2.3,
and
BIND
9.1.2
were
in
widespread
use
on
the
Internet
as
free
software.
However,
the
pur-
chase
of
support
contracts
aids
in
the
continued
de-

velopment of
the
Internet Software Consortium's
~~~:r~~!~:~=~:~~~~~~~Fty~ef:~a
r:.
1974,
adapted
to
the
Digital
VAX
and
PDP-II,
and
now
widely
ported
to
many
systems.
BSD
was
fur-
ther
developed
by
Bill
Joy
and
others

at
the
Univer-
sity
of
California
in
Berkeley,
who
released
it
in
1978.
Joy
subsequently
wrote
the
well-known
vi
editor,
and
co-founded
Sun
Microsystems.
BSD
flourished
with
the
development
of

the
ARPA-
NET,
the
forerunner
to
the
Internet,
and
the
Computer
Systems
Research
Group
(CSRG)
enhanced
BSD
with
32-bit
addressing,
virtual
memory,
and
a
fast
file
system
supporting
long
filenames.

They
further
in-
troduced
BSD
Lite
which
was
BSD
without
the
li-
censed
AT
&T
code,
which
could
be
freely
distributed.
The
CSRG
disbanded
in
1992,
and
the
community
at

large
adopted
BSD
and
developed
FreeBSD.
See
FreeBSD,
Unix,
UNIX.
Berliner,
EmU
(later
Emile)
(1851-1929)
A
German-
born
American/Canadian
inventor
and
musician
who
was
keenly
interested
in
acoustics,
electricity,
and

physics
as
telephone
technology
began
to
emerge.
Berliner
is
best
known
for
music
technologies,
but
also
made
some
significant
contributions
to
historic
telephone
technology.
In
April
1877,
he
filed
a

ca-
veat
for
a patent
on
a
telephone
transmitter
and
six
months
later
is
reported
to
have
demonstrated
sev-
eral
telephone
devices
at
the
Smithsonian
Institution.
In
1878,
he
received
apatent

for
a
transfonner.
Ber-
liner joined
the
Bell
Company
and
later
founded
Deutsche
Grammophon
and
Gramophone
Co.,
Ltd.
F.
Barraud's painting
of
a dog listening
to
a
gramophone (trademarked "His Master's
Voice")
became
the
popular "Nipper
and
the

Gramophone"
trademark
registered
May
1900
by
Berliner.
RCA
adopted
the
popular
symbol,
which
is
still
recognized
more
than
100
years
later.
Berliner
also
founded
the
Esther
Berliner
fellowship
to
support

women
pursu-
ing
scientific
research.
See
Gramophone.
Berners-Lee, Tim (1955- )A
British
physicist
and
programmer,
Berners-
Lee
gained
a
spot
in
the
his-
tory
books
with
his
Web
project
proposal
introduced
in
March

1989,
and
his
demonstration
of
World
Wide
Web
software
in
the
winter
of
1989.
The
rapid
accep-
tance
and
growth
of
the
Web
is
a
tribute
to
the
viabil-
ity

of
this
concept.
Prior
to
that,
Berners-Lee
devel-
oped
Enquire,
while
at
CERN
in
1980,
a hypertext
system
that
no
doubt
formed
the
seed
for
his
Web
project.
In
1994,
he

joined
the
Laboratory
for
Com-
puter
Science
at
MIT.
He
has
won
many
awards
of
distinction for his work, including the 1998
MacArthur
Fellowship.
He
is
the
coauthor,
with
Mark
Fischetti,
of
Weaving
the
Web,
a

book
about
the
ori-
gins
and
development
of
the
World
Wide
Web.
See
World
Wide
Web.
Bernoulli, Daniel (1700-1782) Bernoulli
was
a
Swiss
mathematician
born
in
the
Netherlands,
who
115
© 2003 by CRC Press LLC
Fiber
Optics

Illustrated
Dictionary
pioneered
the
principles
of
fluid
dynamics,
now
used
broadly
in
aeronautics,
electronics,
and
other
fields.
The
Bernoulli
principle
is
derived
from
his
writings
in
Hydrodynamica
which
described
basic

properties
of
fluid
pressure,
density,
and
flow.
Bernoulli box An
electronic,
high-speed
data
mass
storage
and
retrieval
device
based
upon
technology
pioneered
by
Daniel
Bernoulli.
In
general,
the
Ber-
noulli effect
occurs
as

pressure
acts
upon
a
fluid
me-
dium
in
relation
to
the
volume
of
the
fluid.
These
forces
will
equal
changes
in
kinetic
energy
associ-
ated
with
the
fluid
(whether
liquid

or
gaseous).
In
general,
as
fluid
flow
slows,
pressure
increases,
and
vice versa.
As
applied
to
storage technology,
in-
creased
rotational
speed
in
a
magnetic
disk
creates
a
cushion
of
air
that

controls
the
distance
of
the
read!
write
head
from
the
storage
medium.
Daniel
Bernoulli
One
of
the earlier removable computer storage
media, called Bernoulli drives, were named after
Daniel Bernoulli, a mathematician.
Bernoulli-Euler law
In
a
homogenous
bar,
the
cur-
vature
of
its
central

fiber
is
proportional
to
the
bend-
ing
movement.
It
is
a
general
concept,
applicable
to
many
fields
including
elastic
theory
and
mechanical
engineering.
Bernoulli's Theorem in a Field
of
Flow
At
every
point
in

a
steadily
flowing
fluid,
the
sum
of
the
pres-
sure
head,
the
velocity
head,
and
the
height
is
con-
stant.
Berry,Clifford Edward
(1918-1963)
An
intelligent
and
mechanically
gifted
American
who
collaborated

with
J.
V.
Atanasoff
in
the
development
of
one
of
the
world's
first
digital
computers.
Atanasoff
and
Berry
began
working
together
on
the
project
soon
after
Berry
completed
his
Bachelor's

degree
in
electrical
engineering.
The
completion
ofa
prototype
computer
led
to
a
small
grant
to
build
a
working
version,
in
December
1939,
while
Berry
continued
his
graduate
studies.
Berry
then

subsequently
worked
in
corporate
positions
and
applied
for
more
than
40
patents
in
the
116
areas
of
spectrometry
and
electronics,
30
of
which
had
been granted before
his
untimely
death.
See
Atanasoff-Berry

computer.
BERT
bit
error
rate
test/tester;
block
error
rate
test!
tester.
A
diagnostic
device
that
is
used
to
test
data
in-
tegrity
by
transmitting
a
known
pattern of
bits
and
evaluating

the
subsequent
bit
error
rate
(BER),
usu-
ally
on
a
cable
segment.
See
bit
error
rate.
BERTS
See
Basic
Exchange
Radio
Telecommuni-
cations
Service.
bespoken, bespoke
Custom-made,
made
to
order,
made

by
engagement,
requested
item.
Bessel beamA
nondiffracting
optical
beam,
a
recent
technology
that
began
showing
some
exciting
prac-
tical
results
by
the
end
of
the
1990s.
The
potential
for
infinitely propagating
beams

for
manipulating
particles
or
transmitting
information
are
exciting
new
fields
of
experimentation.
By
2001,
U.K.
researchers
had
demonstrated
Bessel
beam
"tweezers"
for
manipulating, stacking,
and
aligning
a variety
of
silica
and
biological

structures.
The
linear
momentum
of
light
and
its
interaction
with
matter
were
exploited
to
trap
particles.
They
also
demonstrated
the
use
ofa
laser
beam
as
an
optical
particle
guide,
moving

1
Ilm
spheres
upward
within
the
microscope
slide
medium
within
which
the
par-
ticles
were
held.
In
addition
to
applications
in
biol-
ogy
and
medical
imaging,
this
technology
may
have

significant practical applications
in
optical fiber-
based
telecommunications.
Bessel
beams
can
be
generated
with
a
glass
element
called
an
axicon.
See
acousto-optic
deflector,
axicon,
laser.
Best
Current
Practice
BCP.
A
process
similar
to

the
Internet
Standards
process,
in
that
specifications
are
submitted
to
the
IESG
for
review,
but
streamlined
to
provide
industry
leaders
with
a
more
flexible,
and
often
quicker,
consensual
alternative
to

the
Standards
Track
specifications
for
resolving
individual
policy
and
operations
issues.
See
Internet
Standards
process.
Best Effort
See
available
bit
rate.
Best EffortCapabilityA
capability
offered
on
some
ATM
networks
that
tries
to

provide
transmission
but
provides
no
guarantees
of
throughput.
Might
be
used
between
two
routers,
for
example.
See
ATM
traffic
descriptor,
RFC
1633.
beta
1.
In
electronics,
the
current
gain
ofa bipolar

transistor
in
a
grounded-emitter
amplifier.
2.
A
ver-
sion
of
software
that
is
mostly
complete,
has
been
in-
house
tested,
but
requires
wider
input
and
trials
from
testers
and
users

outside
the
company.
See
beta
test.
3.
(symb.
-
B)
quartz.
4.
(symb.
-~)
The
second
let-
ter
in
the
Greek
alphabet,
sometimes
used
to
denote
a
specific
angle
in

a
geometric
diagram.
BETA
Business
Equipment
Trade
Association.
A
rep-
resentative
for
many
of
the
large
hardware
manufac-
turers
in
the
computing
industry.
beta site A
location
or
group
of
people
designated

to
test
and
use
a
piece
of
nearly
completed,
internally
tested
software
in
working
conditions
more
nearly
like
those
in
which
the
software
will
eventually
be
used.
© 2003 by CRC Press LLC
beta testing
The

in-house
process
of
testing
and
us-
ing
a
nearly
complete
software
or
hardware
product
to
try
to
detennine
if
there
are
still
bugs
or
problems
of
usability,
consistency,
continuity,
and

ergonomics.
Beta
testing
can
take
months
or
years,
depending
upon
the
state
of
readiness
and
the
complexity
of
the
software.
Some
developers
use
automated
monkeys,
programs
that
systematically
climb
through

the
soft-
ware,
to
identify
bugs
or
flow
problems.
It
is
a
good
process
to
use
in
conjunction
with
human
testing.
In
the
author's
experience,
as
much
as
85%
of

soft-
ware
may
be
commercially
introduced
without
suf-
ficient
beta
testing.
Because
computing
is
confusing
to
the
average
user,
users
are
hesitant
to
complain,
thinking
the
fault
is
in
their

use
of
the
product
rather
than
the
product
itself,
and
sometimes
this
is
true.
But,
upper
managers
often
insist
the
product
has
to
ship
(whether
it's
ready
or
not)
in

order
to
generate
rev-
enues
to
stay
in
business
even
though,
in
most
cases,
it's
bad
economy.
The
cost
of
testing
and
correcting
bugs
before
the
product
ships
is
almost

always
lower
than
the
cost
of
repeated
patches,
upgrades,
techni-
cal
support,
and
loss
of
business
due
to
consumer
dis-
satisfaction
when
firefighting
and
corrections
are
done
after
the
product

ships.
If
cars
were
sold
with
the
same
number
of
defects
as
many
software
products,
consumer
rights
organiza-
tions
would
boycott
the
manufacturers.
The
author
of
this
dictionary
has
contributed

many
hundreds
of
hours
to
beta
testing
and
once
found
more
than
300
bugs
in
two
days
of
testing
in
a
software
product
that
the
manufacturer
insisted
was
"complete,
ready

to
ship,
and
absolutely
bug-free."
There
are
responsible
software
houses
that
engage
in
extensive
testing
and
quality
control,
and
their
efforts
should
be
recognized
and
rewarded.
For
those
that
don't,

caveat
emptor
or
get
your
money
back.
See
alpha
testing,
gamma
test-
ing,
upgrade,
user
acceptance
testing.
BETRS
See
Basic
Exchange
Telecommunications
Radio
Service.
beyond visual range
BVR.
Something
that
is
out-

side
human
sight,
or
in
some
contexts,
out
of
sight
of
human
vision
with
binoculars.
In a
very
general
sense,
it
can
mean
something
distant
or
obstructed.
In
tele-
communications
contexts

it
is
more
often
used
to
in-
dicate
objects,
communications
means,
or
antennas
that
require
'line of sight'
distances
or
unimpeded
pathways
to
be
effective.
See
line
of
sight.
bezel
The
rim

or
edge
ofa
tool
or
piece
of
equipment,
often
angled
or
sloped.
On
a
computer
monitor,
the
housing
edge
around
the
cathode-ray
tube.
BFA
See
Brocade
Fabric
Aware
program.
BFI

1.
See
Bad
Frame
Indicator.
2.
See
British
Film
Institute.
3.
Buckminster
Fuller
Institute.
BFO
See
beat
frequency
oscillator.
BFOC, bayonet FOC
bayonet
fiber
optic
connec-
tor.
A
quick-connect
device
without
a

screw
thread.
BFT
See
binary
file
transfer.
BG,
BGND
background.
BGP
1.
See
Border
Gateway
Protocol.
2.
See
Byz-
antine
Generals
problem.
BHLI
See
Broadband
High
Layer
Information.
bias
1.

Expected
or
consistent
deviation,
inclination
of
outlook.
2.
Deviation
from
expected
value,
sys-
tematic
error.
3.
In
an
electron tube,
the
fixed
volt-
age
that
is
applied
between
the
control
grid

and
the
cathode.
bias distortion
Inconsistencies
or
aberrations
in
the
linearity
ofa
signal.
In
finely
tuned
equipment,
bias
distortion
is
usually
an
undesirable
property.
bias stabilizationA
means
of
controlling
the
bias
in

a circuit
so
that
it
does
not
fluctuate.
Heat
or
signal
variations
can
throw
offbias,
resulting
in
damage
to
components.
See
bias,
bias
distortion.
biasing
To
apply
a
small
amount
of

positive
or
nega-
tive
stimulus
to
a
circuit,
as
in
an
electron
tube,
to
shift
it
in
one
direction
or
the
other.
BIB
See
backward
indicator
bit.
BIBO
bounded
input,

bounded
output.
Input
and/or
output falling between specified values
or
other
boundaries.
A
concept
used
in
linear
mathematics
theory
and
calculations
and
in
data
networking
analy-
sis
of
traffic
flow.
While
many
models
for

network
traffic
are
based
on
unlimited
or
scalable
queues,
for
the
purposes
of
modeling,
testing,
or
design,
it
is
of-
ten
practical
to
establish
bounds
for
input
and
output.
BICEP

See
bit-interleaved
parity.
biconical antenna A balanced
broadband
antenna
which
resembles
a
bowtie
in
the
sense
that
it
has
two
metal
cones
mounted
in
the
same
axis,
that
meet
at
the
narrow
ends

where
the
feed
line
is
attached.
The
orientation
of
the
assembly
affects
its
polarity.
It
is
suitable
for
transmissions
in
the
VHF
range.
BICSIA
not-
for-profit
international
telecommunica-
tions
association

headquartered
in
Tampa,
Florida.
There
are
regional
offices
in
Australia,
Brazil,
and
the
U.K.
BICSI
provides
educational
resources,
technical
pub-
lications,
and
support
for
cabling
distribution
design
and
installation.
It

was
originally
established
in
the
early
1970s
as
the
Building
Industry
Consulting
Ser-
vices,
International,
but
is
now
formally
known
as
BleSI: A
Telecommunications
Association.
/>BID
bridge
identification
code.
See
bridge.

BIDDS
See
Base
Information
Digital
Distribution
System.
BiDi bidirectional.
1.
Capable
of
communicating
in
two
directions
either alternately
or
simultaneously.
2.
Oriented
or
pointing
in
two
directions,
as
direc-
tional
antenna
components

with
two
main
receiving
or
transmitting
elements.
bidirectional
reflectance
distribution
func-
tion
BRDF.
A
function
describing
light
reflectance
from
a
surface
at
a
given
orientation
from
a
source
of
illumination

incident
from
a
given
direction.
See
Lambert's
law.
bidirectional line-switched ring
BLSR.
A
fault-tol-
erant
topology
for
SONET
that
overcomes
some
of
the
problems
associated
with
breaks
in
basic
point-
to-point
ring

topologies.
In
most
ring
topologies
a
secondary
ring
is
in
place,
in
case
ofa
failure
in
the
primary
ring.
In
local
area
networks,
this
is
a practi-
cal
solution,
but
on

long-haul
phone
networks,
for
117
© 2003 by CRC Press LLC
Fiber
Optics
Illustrated
Dictionary
example,
it
involves
the
costly installation ofa sec-
ondary
cable
that
is
rarely
used.
In
BLSR,
ifa failure
occurs,
the
bidirectional portion of the link
is
en-
gaged,

and
the
traffic
is
routed
in
the
opposite direc-
tion
around
the
section
that
has
failed.
In
fiber optic
cables,
this
is
a very
fast
transition
and
wouldn't
be
noticed
by
endusers
under

most
conditions.
BIDS Broadband Infrastructures
for
Digital
TV
and
Multimedia Services. An
ACTS
project
to
provide a
comprehensive analysis
of
future broadband digital
television
and
interactive multimedia services for
European
users.
BIDS
has
established a database
of
information gathered
from
interactive digital
TV
tri-
als

and
has
analyzed a number ofcase studies.
See
BBL,
BLISS,
BONAPARTE,
BOURBON,
BROAD-
BANDLOOP,
BTl,
UPGRADE,
WOTAN.
bifurcated routing A routing technique that splits
data
traffic
so
that
it
continues
through
multiple
routes
(technically
it
would
be
two
routes,
as

bifurcated
means split
into
two
branches).
BIG
See
broadband integrated
gateway.
big-endian
Stored
or
transmitted
data
in
that
the
most
significant
bit
or
byte precedes
the
least significant
bit
or
byte.
Many
file
incompatibilities between

com-
puter
systems,
in
which
the
file
formats
are
otherwise
almost identical, are
due
to
platform conventions
about
whether
the
data
is
stored
in
big-endian
or
little-
endian
form.
BIGA
Bus
Interface
Gate

Array.
Technology built
into
Cisco Catalyst systems
to
receive
and
transmit
frames
from
packet-switching memory
to
its
MAC
local
buffer memory external
to
the
host processor.
Bll
base information infrastructure. The communi-
cations foundation
for
military establishments.
bilateral antenna
An
antenna whose maximum
transmitting
or
receiving poles

are
diametrically
op-
posite,
that
is
180
0
apart
in
a plane.
Bildshirmtext
[trans!.
picture screen
text]
A
German
interactive videotext system from the German
Bundespost.
It
is
similar
to
the French Telecom
Minitel service, except that
the
German Bundespost
did
not provide
the

terminal
free.
See
Minitel.
billboard array antenna
An
antenna array
that
re-
sembles a billboard
in
that
it
uses
a large sheet metal
reflector
behind
the
stacked bipole arrays.
Billing Account Number
BAN.
An
identifier
that
enables telephone carriers
to
bill
individual custom-
ers
or

each
of
multiple
accounts
belonging
to
the
same
customer.
Billing Telephone Number, Billed Telephone Num-
ber
BTN.
In
some
situations,
the
telephone number
billed
may
be
one
ofseveral associated numbers
but,
for
simplicity,
all
the
calls
are
billed

to
one.
This
sys-
tem
is
sometimes
done
with extension
numbers.
In
other situations,
the
main
number used
may
be
dif-
ferent
from
the
number
to
which
the
calls
are
billed,
again, usually
to

simplify accounting
or
billing state-
ments.
billion In North America
and
France,
one
thousand
million
(10
9
-
1,000,000,000).
In
the
U.K.
and
parts
of
Europe, one million million (10
12
-
1,000,000,000,000).
(It
used
to
be
a
huge

number.)
118
BINAC Binary Automatic Computer. Ajoint project
of
1.
Mauchly and
1.
P.
Eckert who founded the
Eckert-Mauchly Computer Corporation.
The
BINAC
was
developed under contract with
the
Northrop
Air-
craft Corporation, unveiled
in
1949,
and
was
histori-
cally significant
not
only
as
a successor to
ENIAC
but

for
its
ability
to
store
data
programmed
using
C-l 0
code
on
magnetic tapes rather
than
on
paper
tape
or
punch cards.
See
ENIAC;
Hopper, Grace Murray;
UNIVAC.
binaries, binary
files
Files
that
have
been
compiled
or assembled

into
machine-readable codes, usually
32-bit executable
files,
that
are
inscrutable
to
most
human beings. Source code
is
higher
level
code (as
in
BASIC,
C,
or
Perl) that
can
more
easily
be
read
and
modified
by
a programmer. Binary
files
can

be
edited directly with a hexadecimal (base
16)
editor.
See
attachment.
binary, base 2 A system of numeric concepts
and
numerals representing quantities
in
terms of
ones
and
zeros with
the
smaller units
on
the right. Thus,
two
in
the
base
10
decimal system
is
written
as
"2."
The
same quantity expressed in binary

is
"10"
or
"00000010" with
the
one
in
the
'twos' position, sec-
ond
from
the
right.
The
columns
from
right
to left
are
thought
of
as
the "ones column," "twos column,"
"fours column," "eights column,"
etc.
so
that
a digit
in
aspecific column indicates

the
presence
or
absence
of
that amount. Thus,
the
following numeral
in
bi-
nary:
00
II 0I0
can
be
transposed
to
decimal
by
add-
ing
its
values: 0+0+ 16+8+0+2+0 =
26.
In
electronics, binary values
can
be
variously repre-
sented

by
pulses ofunequal length,
by
amplitudes
of
specified magnitudes,
by
power
on
or
offconditions,
or
by
different
tones.
Because
most
computers
are
two-state systems,
the
binary number system
is
used
for
programming
and
storage
of
data. Thus, zero

and
one can represent
states such
as
on or off, yes
or
no,
etc.
binary asymmetric channel BAC. A concept used
in
information theory related
to
Markov channels.
As
an
example, images
can
be
modeled
as
binary asym-
metric Markov sources
for
transmission over com-
munication channels.
In
mathematical descriptions
of
the
capacity of physical

or
theoretic structures,
the
concept of
BAC
is
useful
for
surface area calcula-
tions.
binary coded decimal
BCD.
I. A system wherein
each decimal digit
is
coded
into
afour-bit
word.
2.
A
system wherein each octet within
an
ATM
cell
has
each bit
set
to
one of

two
allowable states, i.e., one
or
zero.
3.
A system
of
coding
high
and
low
power
transmissions. For example,
BCD
is
used
by
the
Na-
tional Institute
of
Standards
and
Technology (NIST)
to
represent decimal numbers
in
order
to
dissemi-

nate time code information.
At
the start ofeach sec-
ond
of
the
60-kHz broadcast,
the
carrier power
is
re-
duced
10
dB,
putting
the
leading edge
of
each
nega-
tive-going pulse
on
time.
To
create a binary zero
(0),
full
power
is
restored

0.2
seconds
later.
Alternately,
to
create a binary one (I), full power
is
restored
0.5
seconds later. Position markers are signaled
© 2003 by CRC Press LLC
Binary Phase-Shift
Keying
A
""
if'i"
iA
A 1
,

,
r",
r,
: : : : :
__
cyfl!.~*l:"~~l!.~
,Cl~f+-
ercl~
: :
'.&

'~
A
wave
can
be
altered
in
a variety
of
ways
to
repre-
sent information. By using
two
wavephases,
with
one
of
the
phases shifted by halfcompared
to
the
preced-
ing reference
wave,
it
is
possiblefor the linear
modu-
lation

of
a wave
to
represent
two
values,
zero
(0)
and
one
(1)
which,
in
turn,
can
be
transmitted
in
sequences
of
patterns
to
represent data values
(e.g.,
ASCII
char-
acters). Note that
the
length
of

theperiodand
the
am-
plitude
remain
the
same,
only the phase
is
changed.
Biocomputing Office Protocol
BOP.
An Internet
transaction
protocol
for
transmitting
command
line
and
file
data,
somewhat
analogous
to
SMTP-POP,
but
designed
specifically
to

send
command-line
plus
data
input
file
block
from
the
client
to
the
server
where
it
is
analyzed
and
passed
back
to
the
client
upon
request.
BOP
was
developed
as
an

easier
way
for
nontechnical
professionals
to
access
biocomputing
resources.
The
server
designed
to
implement
BOP
requests
is
called
hopper,
with
SeqPup
used
as
the
initial
client.
BOP
can
be
used

with
anonymous
or
password
access
and
provides
both
deferred
and
interactive processing
modes.
See
bopper.
biometricAn
objective
measure
or
representation
of
a
biological
attribute,
which
may
be
a
physical
char-
acteristic

or
the
output
of
certain
physical
character-
istics
(e.g.,
handwriting).
In
technology
applications,
biometrics
that
are
specific
to
an
individual,
such
as
fingerprints,
iris
or
retina
patterns,
brain
waves,
and

voice
prints,
are
of interest
for
developing
access,
login,
and
authentication
systems.
Fiber
optic
faceplates
are
being
developed
for
use
as
biometric
light-guiding
surfaces
in
conjunction
with
BinHexA
very
useful
software

archiving/translation
tool
that
can
be
used
to
convert
an
8-bit
binary
file
into
a 7
-bit
ASCII
file
through
run-length
encoding,
so
that
it
can
be
handled
by
7
-bit
systems

that
may
use
different
protocols
but
understand
ASCII.
Many
email
clients
use
BinHex
internally
to
handle
binary
attachments
to
text
messages.
At
the
receiving
end,
the
file
must
be
converted

back
to
its
original
fonn
before
it
can
be
executed
or
otherwise
used
as
origi-
nally
intended.
BinHex
is
a
very
widely
used
appli-
cation
on
many
platfonns
but
is

especially
prevalent
in
Unix
and
Macintosh
environments.
by
restoring
full
power
0.8
seconds
later.
binary
file
transfer
BFT.
Binary
files
are
those
that
have
been
translated
into
a
base
2

system
to
be
more
readily
used
by
a
computer.
Binary
files
cannot
be
readily
transported
over
7
-bit
systems
that
typically
use
ASCII
(or
EBCDIC
on
some
older
systems)
en-

coding
unless
they
are
encoded.
Due
to
the
encod-
ing,
binary
files
cannot
be
directly
read
by
(most)
humans
or
directly
edited
by
most
text
editors,
al-
though
a
hexadecimal

editor
is
sometimes
used
to
make
limited
changes
to
binary
files.
Binary
file
transfers
are
usually
accomplished
by
(1)
encoding
the
file
into
ASCII
with
a utility
such
as
BinHex,
(2)

transmitting
the
file,
and
(3)
re-encod-
ing
it
at
the
destination.
Most
email
clients
now
au-
tomatically
convert
binary
file
attachments.
Multipur-
pose
Internet
Mail
Extension
(MIME)
is
one
of

the
protocols
used
with
mail
clients
to
handle
transpar-
ently
the
encoding
and
decoding
of
attached
files.
binary phase-shift keying
BPSK.
A
type
of
linear
modulation
in
which
the
phase
ofa
constant

ampli-
tude
carrier
signal
represents
two
values
through
180
0
shift
reversals.
When
there
is
no
phase
change,
a
value
of
zero
(0)
is
represented,
while
a
phase
change
rela-

tive
to
the
preceding
wave
period
represents
a
value
of
one
(1).
This
basic
modulation
scheme
is
effective
for
ama-
teur high-frequency radio transmissions and
LowFER-
and
MedFER-band
operations.
BPSK
is
used
in
the

SLOWBPSK
program developed
by
Pawel
Jalocha.
The
system
was
updated
as
PSK31
(phase-shift
keying
31
baud)
by
Peter
Martinez
to
function
over
a
narrow
160-Hz
phase-shift
mode.
binary signaling
Signaling
based
upon

two
states,
whether
it
be
digital
or
analog.
Binary
signaling
is
a
common
fonn
of
modulation
with
a
variety
of
imple-
mentations,
including
arbitrary
binary
signaling,
syn-
chronous
binary
signaling,

antipodal
binary
signal-
ing
(spread
spectrum,
Manchester),
binary
noncoher-
ent
signaling,
binary
orthogonal
signaling
(codewords
placed
at
orthogonal
axes).
See
binary
phase
shift
keying.
binaural
Related
to
two
sound
sources

or
two
sound
receiving
sources,
as
human
ears.
Since
humans
are
accustomed
to
using
two
sound
sources
to
distinguish
the
quality
and
directionality of
sound,
monaural
music
tends
to
sound
somewhat

flat.
Thus,
stereo
(binaural)
sound
systems
have
evolved
to
provide
a
more
natural
representation
of
sound.
BIND
See
Berkeley
Internet
Name
Domain.
bind triangle
In
an
International
Business
Machines
(ffiM)
SNA

implementation,
a
session
setup
message
sequence.
binding post
In
electrical installations, a
screw
ter-
minal with a corresponding nut around which
U-shaped
lugs
or
wrapped
wires
can
be
wound
and
secured
with
the
nut.
Sometimes
there
are
two
nuts,

close
together
so
the
wire
can
be
secured
between
the
two
screws.
Binding
posts
tend
to
be
used
in
tempo-
rary
circuits,
or
in
small
installations.
In
medium-
and
large-scale

telephone
installations,
mounting
blocks
and
punchdown
tools
are
much
faster.
119
© 2003 by CRC Press LLC
Fiber
Optics
Illustrated
Dictionary
detectors/sensors.
This
has
good
potential
for
3D
bio-
metric
imaging,
remote
biometric
sensing,
and

larger
sensing/scanning
areas.
See
faceplate.
BIOS
basic
input/output
system.
A
system
in
read
only
memory
(ROM)
on
some
Intel-based
desktop
computers,
that
supports
the
central
processing
unit
(CPU)
by
supplying

access
to
a
variety
of
input/out-
put
devices,
such
as
serial
ports,
joysticks,
monitors,
keyboards,
etc.
As
these
peripherals
are
basic
to
the
functioning
of
the
computer,
they
are
frequently

used
and
loaded
from
ROM
into
RAM
for
fast
access
as
a
system
comes
online
during
the
powerup
sequence.
Biot, Jean-Baptiste (1774-1862) A
French
profes-
sor
of
mathematics
and
astronomy,
Biot
collaborated
with

Arago
in
studying
the
refractive properties of
gases,
and
discovered,
in
collaboration
with
Felix
Savart,
fundamental
relationships
in
electromagnetic
theory.
The Royal
Society
awarded
him
the
Rumford
Medal
for
his
work
in
the

chemical
polarization of
light.
A
crater
on
the
moon
is
named
after
Biot.
See
Biot-Savart
law.
Biot-Savart law
In
electromagnetics,
the
magnetic
field
produced
by
a
current
flowing
through
a
con-
ductor

may
be
described
as
a
vector
product
inversely
related
to
the
distance
ofa
point
in
the
magnetic
field
to
the
source
current.
It
is
similar
to
Coulomb's
law
for
electrical

relationships.
Using
integrals,
the
com-
putation
may
be
applied
to
various
arrangements
of
conducting
sources
by
breaking
the
system
down
into
smaller
components.
See
Ampere's
law,
Coulomb's
law,
Gauss's
law,

right-hand
rule.
BIP
See
bit
interleaved
parity.
biphase codingA
networking
bipolar
coding
scheme
in
which
clocking
information
is
carried
in
the
syn-
chronous
data
stream
without
separate
clocking
leads.
biphase-shift keying
BPSK.

A
simple
type
of
modu-
lation
scheme
used
in
digital
satellite
transmissions.
In
BPSK,
each
phase
of
the
carrier
wave
is
shifted
once
with
each
complete
cycle,
with
a
shift

indicat-
ing
the
change
of
the
value
(from
one
to
zero
or
zero
to
one).
See
binary
phase-shift
keying.
bipolar
1.
Having
two
mutually
opposing
or
repel-
ling
forces,
characteristics,

or
viewpoints.
2.
Having
two
poles.
3.
Acircuit
with
both
positive
and
nega-
tive
polarity
or
alternating
between
positive
and
nega-
tive
polarity.
4.
In
electronics,
a
structure
prevalent
in

integrated
circuits
(ICs).
5.
A
device
having
both
majority
and
minority
carriers.
6.
Having
electromag-
netic
characteristics
alternating
between
two
poles.
7.
A
type
of
signaling
in
digital
transmissions
in

which
a
binary
value
represents
a
signal
amplitude
of
either
polarity,
and
no
value
represents
zero
amplitude.
bipolar receiver A
type
of
telephone
receiver
used
extensively
in
the
Bell
System.
It
improved

on
ear-
lier
technology
by
using
new
magnetic
alloys
and
employing
a
different
acoustical
system
for
the
dia-
phragm.
See
ring-armature
receiver.
bipolarsignalA
signal
with
two
nonzero
polarities;
it
can

represent
two
states
or
three
states
in
a
binary
coding
scheme.
See
bipolar.
bipolartransistorA
semiconductor
commonly
used
in
oscillators,
switches,
and
amplifiers.
120
birdie
1.
Twittering,
squealing,
or
whistling
noise,

often
high-pitched.
Birdie
is
a descriptive
term
for
auditory
interference associated
with
electrical
cir-
cuits.
In
older analog phone circuits, overloading
sometimes
caused
crosstalk (conversations
bleeding
into
one
another)
or,
more
commonly, birdies.
In
amateur
radio
systems,
birdies

may
result
from
ra-
dio
frequency
(RF)
leakage
from
nearby
devices.
In
studios
with
both
amateur
radio
and
computer
equip-
ment
close
together,
it
may
be
necessary
to
power
down

everything
to
a skeleton
system
and
gradually
add
them
back
in
to
locate
sources
of
birdies.
Moni-
tors,
cables,
and
unshielded
devices
are
common
cul-
prits;
even
a
computer
keyboard
can

cause
birdies.
In
circuit
boards,
birdies
may
result
from
improper
grounding. Homemade or commercial radio fre-
quency
(RF)
sniffers
or
more
sophisticated
spectrum
analyzers
can
help
locate
sources
of
radio
frequency
leakage.
Proper shielding
and
grounding,

line
filters,
and
toroids
can
help
reduce
birdies.
If
the
birdies
can-
not
be
easily
eliminated,
it
may
be
necessary
to
note
the
frequencies
at
which
they
occur
and
work

around
them.
2.
Alightweight
cable
or
wire
installation
ac-
cessory
device.
Once
the
conduit
has
been
installed
for
awiring/cabling installation, a
birdie,
attached
to
the
wire
by
a
long
lead,
can
be

blown
with
a
com-
pressed air
tool
so
that
it
"flies"
through
the
conduit,
with
the
wire
subsequently pulled
through
using
the
birdie
as
a
lead.
See
pulling
eye,
snake.
birefringent A
material

with
a
molecular
structure
patterned
the
same
along
two
axes
but
differently
along
the
third.
In
a light-admitting material,
this
anisotropic
structure
will
influence
properties
such
as
the
index
of
refraction,
which

will
vary
depend-
ing
upon
the
angle
of
incidence
of
any
light
that
en-
counters
the
substance.
Observe
a
pebble
in
a
bowl
ofwater
and
one
pebble
will
be
visible,

a little offset
from
its
actual
location.
The
offset
is
due
to
the
index
of
refraction
of
the
wa-
ter compared
to
the adjacent
air.
If
you look
at
a
pebb
Ie
through
a
translucent

birefringent
material,
de-
pending
upon
the
angle,
you
may
see
two
pebbles
be-
cause
birefringent materials
are
doubly
refractive.
Calcium
carbonate
(CaC0
3
)
is
an
example
ofa
com-
mon
natural

substance
with
birefringent
properties.
See
anisotropic,
Iceland
spar,
index
of
refraction,
re-
fraction.
birefringent filter A
mechanism
for
filtering
wave-
lengths
using
intrinsic birefringent
properties
of
ma-
terials
used
in
the
filtering
component.

Birmington Wire Gauge A
gauge
standard
for
de-
scribing
the
diameter of
iron
wires
(nonferrous
wires
are
described
with
American
Wire
Gauge).
The
thin-
ner
the
wire,
the
higher
the
number
from
1
to

20,
ex-
clusive
of
the
coating.
See
American
Wire
Gauge.
bis
Second,
update,
revision,
encore.
In
the
V
Series
Recommendations
of
the
ITU-T
related
to
telecom-
munications,
his
indicates
a

second
version
or
update
to
a previously
numbered
standard.
This
was
prob-
ably
substituted
for
a
revision
number
to
prevent
con-
fusion
between
the
series
number
and
revision
level.
Similarly,
ter

designates
three,
or
third.
© 2003 by CRC Press LLC
BIS
1.
See
Bank
for
International
Settlements.
2.
bor-
der
immediate
system.
BISDN
See
B-ISDN.
BISSI
Broadband
Inter-Switching
System
Interface.
BIST
built-in
self-test.
Testing
capabilities

included
with
a
system.
Many
consumer
laser
printers
have
test
modes
that
will
create
a printout detailing
the
oper-
ating
parameters,
settings, status,
and
problems, if
there
are
any
that
can
be
reported
on

paper.
Some
of
the
newer
printers
also
have
LED
screens
or
Ether-
net
links
so
test
results
can
be
reported
on
a built-in
monitor
or
connected
computer
system.
Bisync
(pron.
bye-sink) Binary

Synchronous
Com-
munication
Protocol.
Acharacter-oriented serial
net-
work
protocol
that
was
developed
in
the
1960s,
at
a
time
when
IBM
dominated
the
network
market.
It
is
now
mainly
supported
as
a legacy protocol.

bisynchronoustransmissionA
transmission
that
can
flow
in
two
directions
on
the
same
line
or
channel,
usually
at
the
same
time.
Traditional wire
line
tele-
phones
are
bisynchronous, whereas
some
types
of
radios
or

intercoms
transmit
only
in
one
direction,
or
in
one
direction
at
a
time.
bit binary
digit.
A basic unit of
digital
information
with
two
(bi-)
states. Many
schemes
for
signaling
binary
states
have
been
developed:

on/off
(early
tele-
graphs),
high/low,
one
or
zero
(mark
or
space,
data
bits),
black/white,
dot/dash,
etc.
bit-interleaved parity
BICEP.
InATM
networks,
an
error-monitoring
method
implemented
at
the
physi-
cal
(PHY)
layer.

The
link overhead contains a
check
bit
or
word
for
the
previous
frame
to
flag
errors.
bit-oriented Data communications that
can
encode
control
information
in
single-bit
data
units.
bit-oriented protocol
BOP.
In
general, a network
control protocol functioning
at
the
data

link
layer.
There
are
variations
on
bit-oriented protocols
typi-
cally
used
for
synchronous transmissions, including
Synchronous
Data
Link
Control
(SDLC),
Advanced
Data
Communication
Control
Procedures
(ADCCP),
and
High Level Data Link Control (HDLC).
See
Transparent
Bit-Oriented
Protocol.
bit bucket slang A mythical container

into
which
unwanted
or
unused
code,
email,
chad
from
punch
cards,
or
other
computer information
is
discarded
or
lost.
Infonnation
may
also
be
deliberately discarded
by
sending
it
to
the
null
device (dev/null) bit

bucket.
See
chad,
leaky
bucket.
bit
error
A
fault
condition
in
which
the
value
of
an
individual
bit
is
changed
by
transmission or
data
in-
terpretation
errors.
bit
error
rate
BER.

Ameasure oftransmission
qual-
ity,
usually
expressed
as
a ratio oferror bits
to
total
bits
received.
A
high
bit
error rate
does
not
necessar-
ily
result
in
a
faulty
transmission.
Error-detecting
and
correcting
algorithms
are
incorporated

into
most
cur-
rent
transmissions
protocols.
However,
a
high
BER
may
result
in
slower transmissions, smaller packets,
a higher
percentage
ofretries,
and
perhaps
even
the
necessity
to
connect
several
times
to
complete a
file
transfer,

for
example.
bit interleaved parity
BIP.
In
ArM networking, a
method
used
at
the
physical layer
to
monitor
the
er-
ror
performance
of
the
link.
Acheckbit
or
check
word
is
sent
in
the
link overhead covering
the

previous
block
or
frame.
Bit
errors
in
the
payload
will
be
de-
tected
and
may
be
reported
as
maintenance
informa-
~~~~~~:;~~
~::~~e~~~~s.f~7~~
:'J~:~r
]1_
In
ATM
trunking,
when
the
BFrame

is
created
on
in-
gress,
a
BIP
is
generated
and
remains
until
the
cell
is
extracted
on
egress
ofa
switch.
Cells
may
be
dropped
ifa
BFrame
parity
error
is
detected.

Payload
data
may
be
BIP-checked separately
and
does
not
necessarily
result
in
dropped
cells.
In
SONET
implementations, distinctions
are
made
between
section
(BIP-B
1),
line
(BIP-B2),
and
path
(BIP-B3)
overhead,
depending
upon

which
part
of
the
path
is
specified.
Layers
are
hierarchical
in
SONET
such
that
if
section
parity
is
correct,
the
layers
beneath
it
should
also
be
correct.
BIP
is
described

more
fully
in
Bellcore
documents
and
in
ANSI
Tl.105.
See
coding
violation.
bit line
BL.
Aconcept
in
array-based
memory
tech-
nologies
to
designate
the
location ofa
specific
bit,
often
in
conjunction
with

a
word
line
(WL).
The
word
and
bit information
may
be
combined
into
a binary
address
to
indicate
the
row
and
column
of
an
array
element,
especially
in
a
20
array.
bit pipe

1.
A
generic
descriptor
for
the
physical
or
data
transmission
line
ofa
digital
circuit.
A
wider
pipe
is
considered
to
have
more
capacity
than
a narrow
pipe or pipeline. A
bit
pipe need
not
connect

sepa-
rate
devices
or
systems;
a pipe
may
be
established
between
two
processes
on
one
device.
2.
A
telephone
circuit
used
to
transmit
digital
data
packets.
bit robbing A
process
of commandeering
bits
in

a
transmission
for
something other than their usual
purpose.
Extra bits
may
be
robbed
to
convey
signal-
ing
information, especially
if
the
signals
are
only
oc-
casionally
needed.
See
robbed-bit
signaling.
bit stuffing
See
zero
bit insertion.
bitmap

1.
A
point-by-point
digital
encoding
of
graph-
ics
data
for
transmission,
storage,
or
display.
The
dis-
played
image
does
not
necessarily reflect
the
format
of
the
image
file.
For
example, a vector
file

may
be
represented
as
a
bitmap
or
pixmap
image
on
aprinter
or
computer
monitor,
or
a
pixmap
file
may
be
con-
verted
to
a continuous
tone
image
when
printed
to
a

dye
sublimation printer.
2.
A pixelated image.
An
image
(picture or
font)
represented by
discrete
dots
on
a monochrome
display,
which
is
typically
white,
green,
or
amber (technically a multicolor
image
is
called apixmap rather
than
a
bitmap).
Grayscale
im-
ages,

with
varying
degrees
of
intensity
on
amonitor
or
varying
sizes
of
monochromatic
dots
on
aprinted
page,
are
often
referred
to
as
bitmap
images,
although
they
may
be
closer
to
pixmaps.

Abit
in
computer
data
does
not
map
directly
to
apoint
on
the
output
device
(in
fact,
several
bits
are
usually
needed
to
encode
one
image
point).
In
the
context
ofa

bitmap,
the
term
bit
is
used
in
its
lay
meaning
to
indicate a
small
amount,
a section,
or
an
individual point of
the
displayed
im-
age.
See
raster, pixels,
vector.
121
© 2003 by CRC Press LLC