Fiber Optics Illustrated Dictionary - Part 94 potx

Fiber
Optics
Illustrated
Dictionary
device-supporting
software
applications.
TAPI
can
be
used
to
create
call
control
software
for
telephony
de-
vices for computerizing common functions
and
sought-after
features.
As
an
example,
TAPI
can
be
used
to

create
a Caller ID-type
function
on
a
com-
puter,
with
the
computer
answering
a Caller
ID-en-
abled
phone
line,
assessing
the
Caller
ID
information,
and
perhaps
relating
it
to
a
database
of
names

or
other
information
associated
with
the
number
and
logging
the
call
or
notifying
the
user
of
the
call.
Since
not
all
phone
systems
are
equipped
with
TAPI
interfaces,
there
are

now
third
parties,
such
as
Ryan
Technologies,
that
provide
protocol
conversion
mod-
ules that enable TAPI-based applications
to
link
through
the
module
to
the
phone
system.
In
1999,
Siemens
extended
the
utility ofTAPI
by
introducing

a
TAPI
interface
compatible
with
a national
ISDN
terminal.
This,
in
conjunction
with
the
Optiset
phone,
turns
a
computer
into
a
powerful
telephony
terminal.
See
Telephony
Services Application Programming
Interface.
Telephony Routing over
IP
TRIP.

Apolicy-driven
inter-administrative domain protocol for routing
voice-over-Internet
calls,
developed
by
the
IETF
IP
Telephony
(iptel)
working
group.
TRIP
is
indepen-
dent
of
the
signaling protocol
used.
It
uses
Border
Gateway
Protocol
(BGP-4)
to
distribute routing
in-

formation
between
administrative
domains.
It
thus
enables
digital telephony calls
to
be
routed
between
digital
network
domains
and
supports
the
exchange
of
routing
information
between
providers,
thus
build-
ing
up
a
forwarding

information
base.
In
August
2001,
TRIP
was
published
as
an
Internet
Draft
and,
in
September
2001,
was
submitted
to
the
IESG
for
consideration
as
a
proposed
standard.
TRIP
may
also

be
a part of
future
protocols
for
the
propa-
gation
of
routing
information
between
gateways
and
their associated signaling
servers
(a
process called
gateway
registration).
Telephony Services Application Programming
Interface
TSAPI.
A
set
ofguidelines developed
by
a
group
of

developers, including Novell, Inc.
and
AT&T,
for
interconnecting corporate telephone
sys-
terns
into
the
data
network
server
in
medium
and
large
business
networks.
The
specification describes
the
physical
link
that
can
be
used
to
implement
software-

based
call
control
from
a private branch exchange
(PBX)
switch,
for
example,
so
that
control
is
handled
from
the
originating
point
in
the
local
area
telephone
network.
Thus,
TAPI's
call
tracking
capabilities
make

it
more
powerful
and
suitable
for
enterprise
environ-
ments
than
the
more
desktop-oriented Telephony
Application
Interface
(TAPI).
See
Telephony
Appli-
cation
Interface.
telephoto, telephotography
Visual
information
con-
veyed
through
conventional photographs
or
digital

photographs
from
data
received
remotely.
Journalists,
geographers,
navigators,
and
others
use
telephotos
to
send or receive visual information from remote
sources
through
wired
or
wireless communications,
and
to
print
them
in
various
resolutions
through
pho-
tographic,
laser,

or
other
means.
Satellite
photos
of
922
the
Earth's surface
are
extremely popular examples
of telephotos.
Many
of
the
images
now
printed
in
national
newspapers
are
telephotos
sent
through
wire-
less
modems
by
journalists using

digital
cameras
and
laptops.
Teleport Communications Group
TCG.
At one
time,
a national competitive
local
telecommunica-
tions
provider
with
fiber
optic
SONET
networks
in
over
50
large markets, acquired
in
early
1998
by
AT&T.
teleprinter
I.
Teletypewriter.

2.
A
Western
Union
trade
name
for
printing
telegraph
terminals.
See
telex.
TelePrompt Project A European Community
(EC)
project
funded
by
a
consortium
of
academic
and
com-
mercial
groups
designed
to
develop
and
further tech-

nology-based distance learning resources
for
Euro-
pean
teleworkers.
The
term
teleworking
in
Europe
is
roughly equivalent
to
the term telecommuting
in
North
America.
teleran An aerial navigational guidance
system
em-
ploying information received through television
waves
and
radar
transmitted
to
aircraft
by
ground
sta-

tions.
TELESA
See
Telecom
Services Association
of
Ja-
pan.
telesales ABritish
term
for
telemarketing.
Teletype A
name
trademarked
by
Teletype
Corpora-
tion
for
avariety ofteleprinting devices
used
in
com-
munications.
See
teletypewriter.
Teletype Corporation
An early printing telegraph
company,

the
Morkrum-Kleinschmidt Corporation,
which
was
acquired
in
1930
by
the
Bell
System
and
renamed
Teletype
Corporation.
teletypesetter A machine
for
remotely controlling
typesetting
machines.
When
these
were
originally
put
into
service, teletype machines
relied
on
a five-unit

code
that
was
insufficient
to
transmit
all
the
charac-
ters
needed
by
a similar teletypesetting machine.
Thus, a six-unit signal code was developed for
teletypesetters
to
increase
the
size
of
the
character
set
from
32
to
64.
teletypewriter
TTY.
A printing apparatus

which,
in
its
common
form,
resembles
a typewriter
on
a
ped-
estal
with
continuous
feed
or
tractor
feed
paper
so
that
it
can
print unattended. Sometimes
it
is
used
to
send
and
receive signals

over
phone
lines
and
for
trans-
mitting messages
or
computer
data
in
text
form.
The
teletypewriter superseded
key
and
sound
tele-
graph
systems
because
it
could operate unattended,
be
read
by
individuals without knowledge ofMorse
code,
and

achieve
transmission speeds of
60
to
100
words
per
minute.
The
earliest teletype-style print-
ers
and
start-stop synchronization
methods
were
de-
veloped
by
Charles
and
Howard
Krum.
See
Baudot
code;
Krum,
Charles
and
Howard;
telegraph, print-

ing;
Teletype;
telex.
teletypewriter code A five-unit
code
that
employs
elements ofuniform
length.
Start
and
stop
pulses
are
used
to
distinguish
each
character
in
the
transmis-
sions.
See
Baudot
code.
teletypewriter exchange service Any commercial
service which provides teletypewriter communica-
© 2003 by CRC Press LLC
tions

sending
and
receiving
services
through
a
switch-
ing
exchange.
Similar
in
concept
to
a
long
distance
telephone
exchange.
TWX
is
one
such
service of
the
Bell System, established in 1931, subsequently
owned
by
AT&T.
See
Telex.

Compact Television Camera
A tiny television camera, not much bigger than a
human hand, designed in the days when television
cameras were large and heavy. The technology was
designed
for
the demandingtask
of
space observation
and
very
long-distance
communications
by
the
Marshall Space Flight Center. Similar cameras were
quickly adapted
for
commercial telecommunications.
[NASA/Marshall Space Flight Center image detail,
date unknown.]
television
TV.
A system
of
sending
and
receiving
broadcast
moving

images
(even if
the
object
in
the
transmission isn't
moving),
usually
in
conjunction
with
sound,
although
some
closed-circuit television
systems don't include sound circuitry. Television
broadcasts can
be
transmitted through air
or
over
cables,
with
cable
TV
(CATV)
increasing
in
popu-

larity.
Air transmissions
are
captured
with
a televi-
sion
antenna designed
for
a portion of
the
broadcast
spectrum
(although three-in-one
antennas
exist
for
UHF,
VHF,
and
FM
signals).
At
the
receiving
end,
a
television set (tuner
and
monitor combined),

or
a
VCR
tuner
and
monitor
are
typically
used
to
display
the
broadcast.
television
broadcast band
The
various
frequencies
which
are
assigned
and
regulated
for
television
broad-
cast
transmissions.
Due
to

the
proliferation of
pro-
gramming
and
the
increased availability of
access
through
satellite
transmissions,
there
is
constant
pres-
sure
to
increase available frequencies
and
channels,
and
hundreds
of
programming channels
are
now
available.
See
band allocations
for

a
chart.
television
camera Alens-equipped, optical-sensing
pickup
device
designed
to
capture
moving
images
and
transmit
or
pass
them
on
to
receiving,
editing,
and
broadcast
equipment.
The
type
of
signal
generated
by
the

camera
varies according
to
the
receiving or edit-
ing
equipment,
and
varies
from
country
to
country.
Television
cameras
have
traditionally
been
expensive,
large,
heavy,
analog, high-resolution apparatuses.
This
is
all
changing,
with
small
handheld digital
and

Common Television Broadcast Formats
Name
Abbreviation
Notes
National
Televisions
Systems
Committee
NTSC
The
North
American
standard
since
the
1950s.
525
vertical
lines.
NTSC
uses
negative
video
modulation
and
FM
sound.
Phase
Alternate
Line

PAL
The
predominant
standard
in
the
United
Kingdom
and
parts
of
Western
Europe
since
the
early
1960s.
625
vertical
lines.
There
are
a
number
of
variations
of
the
PAL
system,

including
PAL-B,
PAL-H,
PAL-M,
etc.
PAL
uses
negative
video
modulation
and
FM
sound.
Sequential
Color
and
Memory
SECAM
Developed
in
France
and
used
in
North
Africa,
Russia,
and
parts
of

Europe
since
the
early
1960s.
625
vertical
lines.
There
are
a
number
of
variations
of
the
SECAM
format,
including
SECAM-B,
SECAM-H,
etc.
High
Definition
Television
HDTV
Introduced
in
Japan
and

proposed
as
a
global
standard,
but
not
readily
adopted
by
American
and
other
manufacturers,
some
of
whom
would
prefer
to
enhance
current
standards
rather
than
adopt
a
new
one.
1125

vertical
lines
at
60
frames
per
second.
HDTV
is
supported
by
some
Internet
push
channels
and
can
be
viewed
with
an
interface
peripheral
and
a
computer
with
a
fast
connection.

Multiplexed
Analog
Components
C-MAC
Developed
in
the
U.K.
and
recommended
by
the
EBU
as
a
European
standard.
923
© 2003 by CRC Press LLC
Fiber
Optics
Illustrated
Dictionary
analog
personal
cameras
beginning
to
rival
the

qual-
ity
of traditional
TV
cameras
for
only
a fraction of
the
price.
See
NTSC,
PAL,
SECAM.
television history
Television,
perhaps
more
than
any
other of
the
major communications technologies,
arose
in
fits
and
starts
in
the

late
1800s
with
many
geographically
diverse
announcements
of
success
and
few
demonstrated
working
systems.
One
of
the
im-
portant
discoveries
in
the
history of television
was
the photoconductive characteristics
of
selenium,
which
responded
to

the
amount
of
light
hitting
the
surface. A
French
researcher,
M.
Senlacq, suggested
in
1878
that
selenium
might
be
used
to
register
the
shapes
of
dark
and
light
areas
on
documents.
British

researcher
Shelford
Bidwell
was
able
to
successfully
transmit silhouettes
by
1881,
and
the
now
famous
German inventor, Paul Nipkow, after
whom
the
Nipkow
disc
is
named,
patented
an
electromechani-
cal
television
system
in
1884.
But

the
transmission
of
moving
images
and
shades
of
gray
in
high
enough
resolutions
to
be
practical
eluded
the
early
inventors.
Although
patents
for
television-related technologies
began
to
appear
in
the
late

1800s,
it
was
not
until
the
1920s
that
television transmission
and
reception
as
we
know
it
was
demonstrated
by
inventors
such
as
John
L.
Baird
in
the
west
and
Kenjito
Takayanagi

in
Asia.
Baird's
first
significant
success
was
in
1926,
the
same
year
Tekayanagi
transmitted
Japanese
script
with
a
cathode-ray
tube.
In
the
U.S.,
a
precocious
15-year-old,
Philo
T.
Farns-
worth,

described
an
idea
for
a
television
to
his
school-
mates
and
reportedly
showed
a
sketch
to
his
teacher
in
1922.
In
1927
he
succeeded
in
building a
working
model.
Experimental
television

stations
sprang
up
in
the
late
1920s
and,
by
the
mid-1930s,
regular
public
broad-
casting
began
to
develop.
In
Europe,
television
im-
ages
were
being
transmitted
by
1931.
Television
sets

were
available
by
the
late
1930s,
but
it
took
time
before
the
technology
became affordable
for
home
use.
By
the
late
I
940s,
there
were
at
least
20
broadcast
stations
in

North
America,
with
hundreds
of
hopefuls
clamoring
for
the
limited
licenses.
Black
and
white
televisions
came
into
widespread
use
in
the
1950s
in
North
America
and
color television
was
common
about

15
years
later.
By
the
mid-1980s,
melon-sized
portable
televisions
became
inexpensive
and
wrist-sized consumer
TVs
had
been
developed.
Commercial
sponsorship
provides
much
of
the
fund-
ing
for
television
in
North
America,

thus
controlling,
to
some
extent,
the
type
of programming
which
is
available,
influenced
by
majority consumer
demand
or
perceived
viewer
preferences.
In
many
other
coun-
tries,
television
is
funded
and
controlled
by

local
gov-
ernments.
The
next
major
step
in
television broadcasting
was
the
launching
of
communications
satellites
such
as
the
Telstar
2
in
1962
which
permitted
intercontinen-
tal
communication.
Commercial
application of
sat-

ellite
television
broadcasting
was
pioneered
by
the
Canadian Broadcasting Corporation through the
ANIK
satellite
in
1972,
followed
in
the
late
1970s
by
924
Turner
and
the
Public
Broadcasting
System
(PBS)
in
the
U.S.
In

North
America,
satellite television broadcasts
can
now
be
received
by
consumers
on
small parabolic
dishes
that
are
served
by
monthly
subscription ser-
vices,
with
hundreds
of potential stations available.
Television
is
widely
used
for
mass-media entertain-
ment,
education, distance monitoring,

and
local
se-
curity monitoring.
The
influence oftelevision
on
world culture
is
sig-
nificant
and
substantial,
with
apreponderance of
the
programming originating
in
the
United States.
Thus,
the
role
models
depicted
through
television program-
ming
and
advertising sponsors

have
a strong effect
on
viewers,
and
implicitly
promote
American
values,
styles
of
dress,
and
cultural priorities
to
all
parts of
the
globe.
See
Baird,
John
Logie;
Farnsworth, Philo
T.;
Nipkow,
Paul
Gottlieb;
Nipkow
disc;

Takayanagi,
Kenjito; television; television camera; Zworykin,
Vladimir.
television relay Astation designed
to
pass
on
a tele-
vision
broadcast
signal
to
the
next
station
so
the
sig-
nal
is
protected
from
loss.
The
relayed
signal
is
not
intended
for

reception
by
viewers
until
it
reaches
the
destination station.
television signal
The
coding
of
images
can
be
accom-
plished
in
a
number
of
ways,
and
there
are
several
standards,
each
of
which

is
preferred
in
a different
part of
the
world.
Common
formats related
to
the
broadcast
and
display of
moving
image
signals
are
shown
in
the
Common
Broadcast
Formats
chart.
telework
Work
at
home
or

at
satellite
locations
made
possible
through
computer
and
telecommunications
technologies.
In
1988,
Jack
M.
Nilles proposed a
broad
definition oftelework
as
"

all
work-related
substitutions oftelecommunications
and
related
in-
formation
technologies
for
travel,"

thus, employerl
employee
interactions
across
distance
through
new
technologies.
This
term
is
more
common
in
Europe
and
is
roughly equivalent
to
the
term
telecommuting
in
North
America.
See
ADVANCE
Project,
European
Community

Telework
Forum,
TelePrompt
Project.
telex teleprinter
exchange.
Generic
term
for
a
com-
munications service developed near
the
end
of
the
second
world
war
that
uses
teletypewriters
to
trans-
mit
through
wire
lines
and
automatic exchanges

to
produce a wlitten
message
at
the
destination.
In
Eu-
rope,
this
technology used audio frequencies over
phone
lines.
See
Baudot
code,
Telex,
Western
Union.
Telex
A global message service established
in
the
United States
by
Western
Union
in
the
early

1960s.
This
was
competitive
with
AT&T's
TWX
service.
Telkes, Maria Aphysicist
who
did
pioneer work
in
the
development of
solar
energy
in
the
early part of
the
20th
century.
Solar
energy
has
subsequently
be-
come
an

extremely important
power
source
for
or-
biting communications satellites.
Telnet Protocol Awidely supported
8-bit,
byte-ori-
ented
network
protocol
for
remote
terminal
access,
originating
from
the
days
of
the
ARPANET.
Telnet
allows
the
user
to
log
on

to
another
system
through
a
TCP/IP
network,
and
perform
file
functions
and
other
© 2003 by CRC Press LLC
activities.
Telnet
is
spelled
in
lowercase
when
used
as
a
command
to
launch
a
remote
utility

that
uses
the
Telnet
Protocol.
The
form
of
the
Telnet
command
is:
telnet
[IP_address/host_name]
[port]
(with the command entered
in
lower case).
See
RFC
318,
RFC
854,
RFC
855
to
RFC
861
(various
options).

TELSTAR 1 A historically significant low-altitude
communications
satellite that broadcast
microwave
transmissions
and
tracked
satellites
in
the
1960s.
This
AT&T
endeavor
is
claimed
to
be
the
first
active
com-
munications
satellite, launched
10
July
1962
by
the
United States, although some RCA engineers

launched
a
transmissions
satellite
earlier.
It
is
the
first
transponder-equipped
satellite. Prior
to
this,
satellites
were
passive
transmitters,
but
the
use
of
transponders
for
amplifying
the
signals
was
preferred
from
this

time
on,
and
some
satellites
now
include
as
many
as
ten
transponders.
The
TELSTAR
had
some
early
problems
that
were
fixed
in
1962;
it
ceased
function-
ing
in
1963.
By

1964,
two
more
TELSTAR
satellites
had
been
successfully launched
and
TELSTAR
3-D
was
launched
in
the
mid-1980s.
Telstar
Communications Satellite
The Telstar 3-Dsatellite being
put
into Earth orbit
from thepayloadbay
of
the Space Shuttle Discovery
in the mid-1980s. [NASA/JSC image detail.}
TEM wave
transverse
electromagnetic
wave.
template

1.
Apattern,
guide,
table,
or
mold
used
to
provide
the
basic
configuration,
format,
or
design
for
creating a
new
version, or multiple versions
of
a
project
with
few
or
no
changes.
A
template
is

intended
to
save
time
by
automating
the
creation
of
new
ver-
sions.
A
word
processing template
can
be
used
to
set
up
documents
which
are
reissued
frequently
with
only
minor
changes

(e.g.,
form
letters).
TemporaryMobile Station Identifier
TMSI.
A
dy-
namically
assigned
mobile
station identifier
(MSID).
TENET
See
Texas
Educational
Network.
tensile strengthAdescriptor
for
the
greatest
amount
of
longitudinal
stress
that
can
be
borne
by

a particu-
lar
material
before
it
will
rip
apart.
The
units
used
to
describe
this
property vary
from
industry
to
indus-
try.
It
is
an
important factor
in
many
manufacturing
and
industrial
applications.

tension testerAn industrial
device
that
tests
the
ten-
sion
parameters
in
a
newly
spliced
fiber
optic
cable
assembly.
This
is
often
sold
as
an
option
to
a
clad-
ding alignment splicer. See cladding alignment
splicer.
tera-
T.

A prefix
for
an
SI
unit quantity of
10
12
,
or
1,000,000,000,000. It's a trillion, a
very
large
quan-
tity,
but
considering
there
are
now
hard
drives
with
terabytes
of
storage
space,
it's
not
as
big

as
it
used
to
be.
It
comes
from
the
Greek
root
terat
or
teras
mean-
ing
"monster."
See
peta-,
pico
TERENA
Trans-European
Research
and
Education
Networking
Association.
A
European
network

evolv-
ing
from
the
European
Academic
and
Research
Net-
work
(EARN)
and
the
Reseaux
Associes
pour
la
Re-
cherche
Europeenne
(RARE).
TERENA
was
estab-
lished
from
the
merger
of
these

organizations
in
1994
to
promote
and
participate
in
the
high
quality
inter-
national information infrastructures
to
benefit
re-
search
and
education.
TERENA
includes
members
from
more
than
three
dozen
countries,
as
well

as
a
number
of
high-profile
computer
developers/vendors,
and
the
CERN
and
ACMWF
international treaty
or-
ganizations.
TERENA
has
been responsible
for
BITNET
support
in
Europe
including
data
collection
and
the
distribu-
tion

of
nodes
and
routing
tables.
See
BITNET.
terminal
1.
An
endpoint,
extremity.
2.
Aconducting
device,
often
a
small
metal post or receptacle,
pro-
vided
for
facilitating a
good
electrical connection.
3.
A
device
or
system

which provides
remote
access
to
a central
computer.
4.
An endpoint
in
a
communi-
cations
line,
or
one
which
can
be,
but
is
not
neces-
sarily,
extended
to
other circuits.
Terminal Adapter
TA.
A device
available

in
vari-
ous
configurations
from
anumber of
vendors
,which
provides protocol adaptation
and
interfacing
with
an
~~Fl~~:i~i~~~:~~~::~~~::s~~~~
,.
Terminal EndpointIdentifier
TEl.
An
identifier
for
distinguishing
between
several different
devices
us-
ing
the
same
ISDN
transmission

links.
Values
may
be
dynamically assigned
to
TEIs
ranging
from
0
to
126.
Fixed
TEIs
are
assigned values
between
0
and
63.
The
value
of
127
is
reserved
for
TEl
broadcast,
which

aids
in
carrying
out
management
functions.
An
ISDN
device
must
be
assigned
at
least
one
unique
TEl
value,
either
by
preassignment
or
dynamically,
by
the
local
exchange,
as
needed (sometimes
called

Auto
TEl).
The
TEl
Management
Protocol
is
used
to
dy-
namically
assign
values
in
a request/response inter-
action.
Dynamic
allocation
is
usually
used
on
point-
to-multipoint
links
but
may
be
used
on

point-to-point
links
terminating office In atransmission
such
as
a
phone
call
or
telegraph
message,
the
terminating office
is
the
switching center which
is
the
final
one
that
con-
nects
directly
to
the
subscriber
line
or
other

receiver
of
the
communications.
In
Internet dialup
communi-
cations,
the
local
ISP
would
be
considered
the
termi-
nating
office.
925
© 2003 by CRC Press LLC
Fiber
Optics
Illustrated
Dictionary
TERMITE Aterminology
database
which
contains
all
tenns

appearing
in
printed glossaries of
the
Inter-
national
Telecommunication
Union
(lTD)
since
1980,
contributed
by
a variety of industry professionals,
including
technical
editors
and
translators.
English,
French,
Spanish,
and
Russian
source
tenns
are
in-
cluded.
Access

to
the
database
is
available
through
Telecom Infonnation Exchange Services (TIES).
ITU
activities
are
now
also
being
archived
in
this
database.
/>terminator Aphysical
device
or
setting
to
indicate
the
end
ofa
data
path
in
a connection

in
which
more
devices
may
be
added.
If
a
chain
is
not
terminated,
the
end
of
the
system
is
seen
as
an
open
port
and
the
system
either continues
to
try

to
send
signals
to
(and
to
expect
signals
from)
another
device
that
isn't
there
or,
in
fiber
optic
networks,
to
experience undesirable
back
reflection
and
instability.
SCSI-format cartridge drives sometimes have
autotermination
built
in
to

the
device
and
the
user
may
have
to
use
a specified
port
on
the
device,
if
it
is
the
last
in
the
chain.
Some
devices
tenninate internally
with
a
setting
on
a

switch
or
a
small
internal
or
ex-
ternal
dipswitch.
Other
devices,
such
as
scanners
and
external
hard
drives,
are
terminated
with
an
external
tenninator
attached
to
one
of
the
SCSI

input/output
connection
mounts.
Internal
hard
drives
are
often
ter-
minated
with
a
set
of resistors
that
can
be
removed
or,
in
some
cases,
with
jumpers.
Most
SCSI
chains
can
be
tenninated

with
standard
50-
or
68-pin
SCSI
tenninators,
but
there
are
excep-
tions,
including
aproprietary "black"
SCSI
tennina-
tor
distributed
by
Apple
Computer
for
some
of
their
older
computers
and
certain
Apple

laser printers
that
support
font
storage
on
attached
hard
drives.
On
an
Ether
network
using
"thin" cables
(1
ObaseT),
a tenninator
is
required
on
each
end
of
the
data
bus
if
the
chain

or
"ring"
is
not
closed.
If"thick" Ether
(1
Obase2)
connections
to
a
plug-and-play
hub
in
a
star
topology
are
used,
separate tennination
is
not
re-
quired.
In
a
wired
network,
devices
such

as
SCSI-fonnat
CD-
ROM
drives,
hard
drives,
and
scanners
can
be
chained
along
the
same
data
path,
but
atenninator
is
required
on
the
end
device
(usually
the
one
farthest
from

the
motherboard)
to
prevent
the
system
from
seeking
devices
beyond
the
last
one.
Failure
to
terminate a
SCSI
chain
can
cause
immediate
or
sporadic
prob-
lems
with
data
access
on
the

chained
devices.
In
a
fiber
optic
network,
the
problem
of
back
reflection
can
be
even
more
serious
than
in
wired
networks.
Many
aspects of wired networks
are
designed
to
handle
signals
in
two

directions
along
one
wire.
Even
when
separate
wires
are
used,
the
strength
of
the
data
signal
is
controlled
such
that
damage
to
components
is
unlikely (possible,
but
not
common).
In
fiber

op-
tic
networks,
an
open,
untenninated
port
may
allow
laser
light
to
escape,
which
can
be
a
danger
to
eyes.
Improper
closing
ofa
fiber
port
can
result
in
the
la-

ser
light
being
reflected
back
down
the
waveguide
in
the
wrong
direction.
This
not
only
disrupts
the
path
and
amplitude
of
the
light
data
signals,
but
also
may
926
interrupt

or
damage
the
laser
source.
Passive tenninators
are
most
common,
but
advance-
ments
in
networking
and
greater
demands
on
the
tech-
nology
are
giving
rise
to
various
types
ofactive
ter-
minators.

Longer
cable
runs
and
higher
data
rate
per-
fonnance
may
be
accompanied
by
higher
noise
sen-
sitivity
that
may
be
mitigated
by
active tenninators
with
voltage
regulation.
Active
SCSI
tenninators
may

autoselect between low-voltage differential
(LVD)
and
single-ended
(SE)
modes.
Because of
the
extra
electronics, active tenninators
are
sometimes a little
larger
than
passive tenninators commonly cost
about
50%
more
than
their passive counterparts.
Fiber
optic
tenninators
come
in
a variety of fonnats,
including
SC
and
FC

and
generally
follow
Telcordia
standards.
Some
fiber
tenninators
are
doped
and
are
typically
sold
to
support specific wavelength
ranges.
Many
of
them
resemble
standard
fiber
connectors
but
they
are
designed
to
eliminated

back
reflection
rather
than
to
facilitate
the
attachment of
another
length
of
cable
or
device.
Terrestrial Digital Service
TDS.
Acommercial
pri-
vate
digital
data
transmission
service
offered
by
MCI
to
subscribers over
local
exchange

carrier
(LEC)
TI,
DS-3
systems.
Thus,
customers
would
have
fast
trans-
mission
links
to
MCI
Services.
There
was
some
de-
bate over this service option through
the
Federal
Communications
Commission
(FCC).
TESe
Technology
Subcommittee.
tesla Ameter-kilogram-second unit of

magnetic
flux
density equivalent
to
one
weber per square
meter.
Named
after Nikola
Tesla.
Tesla
coil
An air-core transfonner
for
creating
high-
voltage discharges
at
very
high
frequencies.
Tesla, Nikola (1856-1943) An engineer
and
inven-
tor
born
in
Smiljan Lika (Austria-Hungary)
who
de-

veloped
the
alternating current
induction
motor,
an
essential part ofalternating current distribution sys-
tems.
Tesla
began
his
research
in
Hungary,
and
then
emigrated
to
the
United
States
in
1884.
He
created a
number
of
unique
inventions
and

also
improved
upon
those
of
others.
In
America,
Nikola
Tesla
and
Thomas
Edison
came
into
regular
contact
with
one
another,
not
always
with
happy
consequences,
and
an
enmity
grew
between

the
two
men.
When
it
was
proposed
in
1912
that
the
Nobel
prize
be
awarded
jointly
to
Edison
and
Tesla,
Tesla
eschewed
any
association
with
Edison,
and
the
prize
went

to
a
Swedish
scientist
instead.
Tesla's inventive
mind
turned
power generated
de-
vices
into
interesting applications
such
as
aircraft
power
systems
and
robotic
submarines.
In
1888,
he
was
awarded
a patent
for
an
electromagnetic

motor.
Tesla
eamed
more
than
700
patents
in
his
lifetime
and
produced
many
more
unpatented ideas
and
inven-
tions.
Tesla
was
somewhat temperamental
and
eccentric.
One
of
his
most
practical contributions
was
the

ad-
aptation
of alternating current
into
everyday
appli-
cations.
His
colleague,
George
Westinghouse,
further
implemented
many
ofTesla's
ideas.
The
tesla
unit
of
magnetic
flux
is
named
after
him.
© 2003 by CRC Press LLC
TESP
See
Telecommunications

Electric
Service
Pri-
ority.
test board A
switching
panel
used
for
making
tem-
porary
connections
in
conjunction
with
the
panel
or
equipment
being
tested.
By
diverting
some
of
the
sig-
nals
through

the
test
panel,
problems
can
sometimes
be
more
easily
isolated
or
identified.
A
test
clip
can
also
be
used
for
the
purpose
of
making
quick
tempo-
rary
connections.
See
breadboard,

shunt.
testjack/plugA
connecting
hole
in
acircuit
or
panel
for
inserting
a
corresponding
plug
Gack)
and
cable
for
making
temporary
connections
for
testing
and
maintenance.
Test
jacks
and
plugs
come
in

many
shapes
and
sizes
depending
upon
what
type
of
cir-
cuit
is
tested.
A
telephone
test
set
is
a
portable
tele-
phone
handset
that
has
clips
for
temporary
attach-
ments

to
a
conducting
line
or
test
jacks
for
tempo-
rary
insertion
into
in
a
test
jack
plug
frame.
test
jack
frame
TJF.
In
private branch exchange
(PBX)
telephone
systems,
a
frame
for

inserting
test
cables
for
maintenance
and
testing,
usually
mounted
in
or
near
the
main
PBX
cabinet
and
terminating
the
cabinet
connections.
test pattern
Any
pattern
generated
for
a particular
transmission
medium
that

indicates
the
integrity
of
the
various
characteristics
of
its
signal,
which
may
include
resolution,
signal
strength,
stability,
linear-
ity,
contrast,
brightness,
colors,
sound
range
and
qual-
ity,
etc.
2.
In

video
editing,
a
series
of
bands
of
spe-
cific
colors.
3.
In
television
broadcasting
and
televi-
sion
set
calibration
and
diagnosis,
a
pattern
(known
to
some
as
the
Indian
head

pattern)
which
includes
particular
lines
and
line
widths,
ellipses,
tonal
gra-
dations,
and
numerical
values
that
allow
the
diagnos-
tician
to
determine
problems
and
make
adjustments.
This
test
pattern
was

frequently
used
in
the
1950s
and
1960s
by
local
stations
as
a
visual
signal
to
viewers
to
indicate
that
there
was
no
programming
currently
in
progress,
although
this
use
has

greatly
declined
due
to
the
multitude
of
programming
now
available.
tetrodeA
four-element
vacuum
tube.
The
three-ele-
ment
tube,
called
a
triode,
was
developed
by
Lee
de
Forest.
This
no
doubt

inspired
experimenters
to
try
other
configurations.
The
four-element
tube
followed,
consisting
ofa
filament,
plate,
and
two
grids
rather
than
one.
The
second
grid,
the
tetrode
or
screen
grid,
was
positioned

between
the
first
grid
and
the
elec-
tron-attracting
plate
(anode).
Texas Educational Network
TENET.
A
Texas
edu-
cation
communications
infrastructure
dedicated
to
fostering educational innovation
and
excellence
among
educators
and
students.
TENET
developed
through

the
collaboration
of
the
Department
of
In-
formation
Resources,
the
Texas
Education
Agency,
and
the
University
of
Texas.
TENET
provides
vari-
ous
resources,
including
publications,
discussion
fo-
rums,
and
professional

development
seminars
and
facilities.
/>TFT
See
thin
film
transistor.
TFTP
See
Trivial
File
Transfer
Protocol.
TFTP Multicast Option A
protocol
option
for
the
Trivial File Transfer Protocol (TFTP)
to
enable
multiple
clients
to
concurrently
receive
the
same

file
through
multicast
packets
to
increase
network
effi-
ciency.
TFTP
Multicast
Option
was
submitted
as
an
Experimental
RFC
by
A.
Emberson
in
February
1997.
See
Trivial
File
Transfer
Protocol,
RFC

2090.
theremin An
electronic
musical
instrument
incorpo-
rating
radio
frequency
oscillators
in
which
two
simi-
lar
frequencies
were
combined
to
provide
a
lower,
human-audible
frequency.
This
was
done
by
combin-
ing

a
reference
frequency
with
a
variable
frequency.
The
theremin
was
played
by
interposing
a
hand
to
vary
the
capacitance
between
two
projecting
elec-
trodes,
thus
controlling
the
pitch
and
volume.

It
was
first
constructed
in
1920
and
became
popular
in
the
late
1920s.
The
process
of
mixing
signals
of slightly
different
frequencies
is
called
heterodyning
and
was
incorpo-
rated
into
many

radios
over
the
next
couple
of
de-
cades.
A transistor
version
of
the
theremin
still
ex-
ists'
and
Mystery
Science
Theater
3000
fans
are
fa-
miliar
with
its
eerie
sounds.
It

was
named
after
its
inventor
Leon
Theremin,
who
originally
called
his
invention
an
"retherphone."
See
heterodyning,
Theremin,
Leol1'.
Theremin, Leon (1896-1993) A
Russian
engineer
and
inventor
who
devised
electronic
musical
instru-
ments,
most

notably
the
"retherphone"
(theremin)
while
a
student
at
the
University of
Petrograd.
He
traveled
to
America
in
1927
to
playa
concert,
and
2
years
later
licensed
the
Radio
Corporation
of
America

(RCA)
to
manufacture
a"thereminvox."
While
in
the
U.S.,
Theremin
also
experimented
with
multimedia
concerts,
combining
light
shows
and
dance
with
the
theremin
music,
later
returning
to
do
research
at
the

University
of
Moscow.
See
theremin.
thermal noise
Random
noise
arising
from
heat
gen-
erated
by
the
motion
of
charged
particles.
Thermal
noise
in
electrical
circuits
is
undesirable
if
it
inter-
feres

with
transmission.
thermal circuit breakerAbreaker
mechanism
that
trips
when
heat
generated
by
excessive
current
ex-
pands
the
conductor.
See
circuit
breaker.
thermion
An
electrically
charged
particle
(a
positive
or
negative
ion)
emitted

from
a
heat
source.
See
ther-
moelectron.
thermionic emission
The
emission
of electrically
charged
particles
under
the
influence
of
heat.
Ther-
mionic
emissions
are
characteristic of
hot
cathode-
ray
tubes.
Cathodes
without
thermionic

emissions
are
called
cold
cathodes.
thermionic valve
See
vacuum
tube.
thermistor
An
electrical resistor
comprising
a
semi-
conductor
with
a
high,
nonlinear
temperature
coeffi-
cient.
The
resistance
of
the
semiconductor
varies
suf-

ficiently
in
relation
to
the
temperature
to
make
it
use-
ful
in
a
number
of
applications.
See
thermostat.
thermocouple, thermaljunctionA
device
that
mea-
sures
temperature
at
the
junction ofa pair ofjoined
wires
employing
dissimilar

materials,
with
the
dif-
ference
in
potential
proportional
to
the
temperature,
determined
by
an
instrument
connected
to
the
other
ends
of
the
wires.
927
© 2003 by CRC Press LLC
Fiber
Optics
Illustrated
Dictionary
Semiconductor thermocouple assemblies

are
fabri-
cated
by
connecting
two
dissimilar
metals
and
inter-
connecting
the
thermocouples
in
series. Materials
with a
high
thermoelectric coefficient
are
typically
used
(e.g.,
antimony).
When
the
junctions
are
dissimi-
lar
(e.g., different metals),

the
difference
in
heat
ab-
sorption
can
be
used
to
generate voltage,
thus
signal-
ing
the
detection of
heat.
Treating
one
of
the
metals
to
increase
its
absorption through chemicals
or
col-
oring
may

magnify
the
effect (improve signal-to-
noise
ratio).
See
potentiometer; pyroelectric detec-
tor;
Seebeck,
Thomas;
thermopile.
thermocouple
wire
A
wire
used
with
a
thermocouple
which
is
made
of
iron
or
particular alloys calibrated
to
the
appropriate specifications.
thermodynamics

The
art
and
science
ofheat-related
phenomena,
their properties
and
relationships.
thermoelectron
An
electron (negative thermion)
emitted
from
a
heat
source.
See
thermion.
thermography
Aprinting process
in
which
nondry-
ing
inks
are
treated
to
simulate a raised, engraved

surface.
After
passing through
the
press,
the
ink
is
dusted
with
a
compound
which,
after
the
excess
is
removed,
is
exposed
to
heat,
causing
it
to
fuse
with
the
ink
to

form
a raised surface.
thermopile
A
component
with
broadband
absorption
characteristics suitable
for
detecting radiation
such
as
infrared
light.
Thermopile detectors
are
fabricated
from
multiple thermocouple devices connected
in
series.
They
may
be
made
with wired junctions or
film
junctions,
with

film
versions generally provid-
ing
advantages
of
size,
portability,
and
response
times
over
larger
wired
assemblies.
See
photodetector,
ther-
mocouple.
thermoplastic
A
material
with
industrial
significance
because
it
can
be
heated
and

reshaped
and
rehardened
by
cooling.
It
has
various
uses
including insulating
and
information recording. Contrast with
thermoset.
thermoset
Aresin
or
plastic material which
can
be
shaped
and
cured,
but
once
this
has
been
done,
can-
not

be
reshaped
and
cured
again,
as
with thermoplas-
tic.
Contrast
with
thermoplastic.
thermostat
1.
Asensing
and
regulating
device
trig-
gered
by
temperature
which
is
useful
in
turning
ma-
chines
on
or

off,
for
controlling
fire
safety
devices
such
as
alanns
and
sprinklers,
and
for
regulating
heat-
ing
and
cooling
systems.
2.
A
device
which
regulates
temperature,
by
measuring
it
and
controlling heating

equipment
(or
heating
and
cooling equipment)
in
or-
der
to
maintain
the
temperature
at
the
setting selected
on
the
thennostat.
This
is
usually accomplished
by
triggering
the
heating circuit
when
the
temperature
varies
a

certain
amount
below
or
above
the
desired
setting.
Thermostats
that
can
be
programmed
for
spe-
cific
temperatures
at
scheduled
times
during
the
day
are
increasingly
common.
Temperature regulation
(cooling)
in
large

supercomputing implementations
is
important.
See
thermistor.
THF
See
tremendously
high
frequency.
thin
film
A
very
fine
layer
or
combined
layers
used
to
enhance
or
change
the
properties
ofa
material.
Thin
films

are
typically
"grown"
in
chemical
vapor
deposi-
928
tion
processes.
There
are
many
different
types
of
film
and
their structure
depends
upon
the
chemicals
used,
the
properties
and
combination
of
the

component
lay-
ers,
temperature,
and
other fabrication parameters.
Thin
films
can
be
grown
with
low
dielectric
constants,
making
them
suitable
for
use
in
integrated
circuits
and
as
filters (e.g.,
DWM
ONU
filters).
Magnetic thin

films
have
unusual megnetotransport
properties useful
for
the
development
of
sensing
de-
vices and magnetic recording technologies. Thin
films
can
be
grown
at
high
temperatures
for
use
in
superconductivity research.
Thin
films
have thousands
of
applications
as
filters,
dielectric mirror surfaces, barrier layers, polarizing

layers,
and
more.
Thin
films
can
be
deposited
on
fi-
ber optic filaments
to
filter a signal or prevent
backreflection. Antireflecting coatings
for
optical
lenses
in
eyeglasses
and
imaging
devices
can
be
made
with
thin
films.
Calculators
and

wristwatches
use
sili-
con
thin-film solar chargers.
Traditionally,
thin
film-treated
wafers
were
placed
be-
tween
fiber
endfaces
to
filter
the
light crossing
from
one
fiber
to
the
next.
However,
it
has
been suggested
that

better performance
is
possible
by
stacking be-
tween
20
and
150
layers
of
alternating highllow
re-
fractive-index
films
onto
a substrate
and
using
this
thin
film
component
in
place oftreated wafers.
See
sputtering.
See
Fiber Optic Probes
diagram.

thin
film
transistor
TFT.
Atechnology
used
in
dis-
play
devices
which
creates
a
correspondence
between
a transistor
and
pixel
on
the
screen
so
that
pixels
can
be
independently controlled. Used
in
color
(RGB)

active
matrix
LCD
panels.
This
technology
has
been
applied
to
portable display projectors and similar
devices.
Thompson,
Joseph
John
(1856-1940) An English
experimenter
who
investigated
electricity
and
X-rays.
He
was
awarded a
Nobel
prize
in
physics
in

1906
for
gaseous
conductivity ofelectricity.
Thompson,
Ken
(1943- )Principal
developer,
along
with
Dennis
M.
Ritchie, of
the
Unix
operating sys-
tem
in
1969.
It
is
quite
a distinction considering
its
widespread
use
and
utility.
Unix
has

since
evolved
through
extensive support
by
the
programming
com-
munity
and
exists
in
a variety of
forms,
although
all
bear similar features. Thompson also authored
B,
which
was
a predecessor
to
C.
See
Unix,
UNIX.
Thompson,
William
See
Lord

Kelvin.
Thomson,
Elihu
(1853-1937) Inventor of
one
of
the
first
alternating current
(AC)
generators,
in
1878.
At
the
time,
the
predominant
form
of
power
was
direct
current
(DC).
This
was
a significant achievement
be-
cause

it
enabled
the
transmission
of
much
higher
volt-
ages,
necessary
to
cross
some
of
the
distances
desired.
Improvements
to
the
concept
were
soon
developed
by
William
Stanley.
Thomson
also
experimented,

in
1892, with electric arcs. He collaborated with
Sebastian
de
Ferranti and William Stanley
in
the
development of
the
transformer.
thread
1.
In
piping, a helical indentation used
to
match
and
secure separate
sections.
2.
One
of
a
num-
ber
of
continuing elements, themes, or trains
of
© 2003 by CRC Press LLC
2110

Fiber Optic Probes and Thin Film Filter Technologies
2120
Figures 27a -
27cfrom
a
patent
developed
by
M.
Wach
et al. show different views
of
a
fiber
optic light-scattering
probe consisting
of
a tightly aligned multifiber ring sUlTounding a centralfiber. Stepped index silica core/cladding
fibers are suitable
for
this type
of
device. The centralfiber, insulated
by
a light-bloc/dngfilm
or
coating,
may
be
used

to deliver light while the surrounding
ringfibers
detect it
or
vice versa. Figure
80
illustrates the application
of
thin-
film
filtering to a complex contoured
suiface
(in this case the cone-shapedendface
of
a
fiber
filament
that is coupled
with anotherfiber). Filters such as the
one
illustratedin Figure 80 can help reduce
back
reflection
at
coupledjoints.
Index-matching epoxy
or
gel
can be
used

to
fill
in the
gap
betweenfibers.
.z!!!jz'-
55
E
Figures 55a - 55e illustrate how different configurations are possible
for
manipulating light through adjoining
segments
of
a multifiberprobe. Various endfacepolishes, angles,
and
thin
film
filters
make
itpossible to use the basic
idea in a variety
of
applications. [Diagrams adaptedfrom USPTO
patent
#6,416,234, submitted
August
2000.J
929
© 2003 by CRC Press LLC
Fiber

Optics
Illustrated
Dictionary
thought
related
to
a
common
forerunner.
3.
In
pro-
gramming, a
flexible
process organization
mecha-
nism
by
which
individual
processes
can
use
common
resources,
but
continue
to
operate
unimpeded

by
other
threads,
if
needed,
in
order
to
improve
program
effi-
ciency
or
to
increase simultaneous
access
to
various
system
or
applications
resources.
Common
in
object-
oriented
systems.
thread, discussion
In
online

newsgroups,
a
topic
of
conversation characterized
by
the
same
(or
similar)
subject
line,
and
theme
and
direction
ofdiscussion.
Threads
are
a
very
convenient
way
to
follow
one
line
of
thought
through

the
myriad
opinions
discussed
in
the
general
context
ofa
news
group.
Good
newsread-
ing
software
will
organize
threads
into
groups
and
subgroups
much
the
same
way
computer directories
(folders)
are
organized

on
the
computer operating
system.
Thus,
the
user
can
selectively
open
and
read,
or
close
and
ignore,
a
thread.
three finger salute slang A descriptive phrase
for
rebooting
the
operating
system
(without powering
down
the
system)
with
three designated

keys
held
down
simultaneously
for
MS-DOS/lntel-based
IBM-
licensed
systems
(Ctrl-Alt-Delete)
and
Amigas.
throughput
Production;
output;
nonredundant
infor-
mation
or
items
ofrelevance
moving
through
a
sys-
tem.
Throughput
is
used
in

industrial
and
computing
industries
to
describe
the
efficiency ofa
system
or
end-result ofa
communication
(how
much
infonna-
tion
got
through).
The
measurement
of throughput
is
quite specific
to
the
system
and
infonnation
or
objects

being
trans-
ferred,
so
there
are
few
generalized
standards
for
time
intervals
or
total
data
against
which
to
compare
the
throughput
(end
result).
Nevertheless,
relative
mea-
sures
of
throughput,
as

compared
to
another
manu-
facturer,
another
type
of
machine,
or
when
processed
in
a different
manner,
can
be
very
useful
in
tuning
a
production
line
system.
Relative measures of
data
throughput
in
different parts of a

network,
or
over
different
data
protocols
or
operating systems,
simi-
larly
can
be
used
to
improve
the
configuration
and
efficiency ofa
computer
network.
TI-99/4 A
Texas
Instruments
home
computer
intro-
duced
early
in

1980.
It
featured
16
Kbytes
RAM,
sound
capabilities,
16-color
graphics
on
a
13-inch
color
monitor,
extended
TI
BASIC,
and
cartridge-like
solid
state
program
modules
for
a
list
price
of$1150
U.S.

TIA
See
Telecommunications
Industry Association.
Till
See
tone
in
band.
TIC
See
Token-Ring
interface
coupler.
ticket
In
telecommunications, a
record
ofa
transac-
tion
or
paid
toll,
fare,
or
fee.
The
ticket
indicates

ei-
ther
that
the
transaction
has
been
confinned
and
it's
OK
to
bill
the
client,
or
that
the
transaction
and
bill-
ing
have
both
taken
place
(as
in
many
credit

card
transactions).
Tickets
traditionally
were
on
paper,
but
electronic
tickets
are
becoming
prevalent,
with
online
transactions
sometimes
going
directly
through
to
the
credit
card
company
from
the
vendor without
any
slips

or
other
paper confinnations.
tickler
In
computer
applications,
a
program
designed
930
to
hibernate
until
a
certain
time
or
until
certain
events
take
place,
and
then
become
active
to
remind
the

user
of something
timely
or
important,
such
as
appoint-
ments,
anniversaries,
events,
etc.
These applications
have
variously
been
called ticklers, reminders,
and
naggers.
tickler, electronic
In
electronics, a
feedback
or
re-
generation device consisting of
two
small
coils
con-

nected
in
an
electron
tube,
one
to
the
anode
(in
se-
ries),
the
other
to
the
grid-circuit.
tie
n.
Fastener,
electrical strap,
bundler.
Astrip,
usu-
ally
ofplastic
or
Velcro™,
to
hold

wires
away
from
one
another, bundle
them
together,
or
fix
them
in
place,
sometimes to a
post
or
other secure structure.
tie
line
I.
In
power
systems,
transmission
lines
that
connect
neighboring
systems.
2.
In

telecommunica-
tions,
a
line
for
directly
tying
two
telephone
or
tele-
graph
connections together without
going
through
a
public switching
center,
often called a "dedicated"
line.
For
example,
the
President
might
have
a
tie
line
connected directly

to
top
advisors that doesn't
go
through
any
outside switches
or
connections,
to
en-
sure
security,
reliability,
and
speed
for
the
connection.
In
the
days
before telephone switching centers
and
central
offices
connected
local
telephone
subscribers,

tie
lines
were
common.
For
example,
in
the
1800s,
a
dozen
telephone
or
telegraph
tie
lines
might
be
wired
out
ofa single
office
to
connect
it
with
other
local
businesses.
The

streets
were
often
cluttered
with
hun-
dreds
of
lines
running
between
windows
and
build-
ings
and
the
utility
poles
holding
the
lines
were
com-
plexly
wired
and
difficult
to
maintain.

Tie
lines
are
still
used
for
a variety ofsecurity
and
business-related purposes.
They
are
especially
use-
ful
in
office
complexes composed of
several
build-
ings
that
have
a
large
volume
of
calls
between
the
buildings. A

tie
line
may
be
set
up
to
connect
directly
simply
by
lifting
the
handset
or
pushing a
button,
as
in
a
hot
line.
A
tie
tmnk
connects
to
telephone
switch-
ing

systems
such
as
two
private branch exchange
(PBX)
systems
and
may
require dialing
access
code
prefixes
reserved
for
that
purpose
on
aparticular
sys-
tem
or
the
system
may
be
locally
automated
to
inter-

pret
an
extension
number
to
be
translated
into
a
tie
line
call.
With
the
evolution of voice over digital
data
net-
works,
the
concept of
tie
lines
has
been
adapted
to
computer networking.
Access
concentrators
can

be
used
to
consolidate
separate
voice
and
data
lines
used
for
communications
within
a
company
into
a single
network
and
voice
over
network
communications
can
then
replace traditional telephone
tie
lines.
Thus,
ex-

isting
Frame
Relay
links
used
for
data,
for
example,
could
also
be
used
for
voice
communications,
remov-
ing
the
need
for
dedicated
phone
lines.
tie
trunkA
telephone
(or
telegraph)
line

directly
con-
necting private
branch
exchanges
(PBXs).
See
tie
line.
tie
line control system
In
power
distribution, a
sys-
tem
for
administering
the
amount
of
electrical
energy
purchased
by
asubscriber
(usually
an
industrial
com-

plex)
from
a utility
company.
© 2003 by CRC Press LLC
tie wrap A
plastic,
fabric,
jute
or
other
type
of
tie
material
used
for
holding
together
a
bundle
of
cables
for
ease
of
placement
or
movement
as

a
unit.
Plastic
tie
wraps
sometimes
have
a hook
mechanism
that
catches
and
holds
the
tie
when
it
is
cinched
tight.
Velcro
brand
tie
wraps
are
easy
to
unwrap
and
read-

just, if
needed.
TIES
1.
Telecom/Information
Equipment
and
Ser-
vices.
A
government-to-government
program
which
provides
u.s.
and
Russian
support
for
the
expansion
of
international
commerce
in
high
technology.
This
is
a

subgroup
under
the
U.S Russia
Business
Devel-
opment
Committee
(BDC).
2.
See
Telecom
Informa-
tion
Exchange
Services.
TIFF
Tag
Image
File
Format.
A
very
widely
used
platform-
and
application-independent, lossless,
color,
raster

image
file
format
that
encodes
the
data
as
strips
or
bands.
The
TIFF
format
is
used
in
faxes,
image
processing
programs,
scanned
files,
and
many
graphics
creation
programs.
It
is

well
supported
by
service
bureaus
and
the
printing
and
graphics
design
industries.
Files
are
often
identified
by
the.
TIF
or
.
tiff
file
extensions.
Creation
of
the
format
took
into

consideration
the
needs
of
the
desktop-publishing
industry
and
other
related
graphics
applications,
with
the
goal
of
mak-
ing
image
information
broadly
interchangeable.
TIFF
was
created
to
be
extensible
so
that

it
may
accom-
modate
future
needs.
TIFF
has
gone
through
a
number
of
major
revisions
but,
in
general,
fields
are
identified
with
unique
tags
so
that
various
applications
can
elect

to
include
or
exclude
particular
fields
depending
upon
their
needs
and
capabilities.
The
core
fields
comprise
Baseline
TIFF.
A
TIFF
file
consists
of
three
main
parts:
an
image
file
header,

a
directory
of
fields,
and
the
file
data.
Descrip-
tions
and
definitions
of
baseline
and
extended
fields
are
documented
in
the
TIFF
Technical
Notes
(TTN).
An
adaptation
called
TIFF-FX
has

been
defined
for
facsimile applications. See facsimile, scanner,
TIFF-FX,
TWAIN.
TIFF-FX A
subset
of
TIFF
adapted
to
generating
documents
with
minimal,
lossless
grayscale
and
color
attributes
for
use
as
facsimile
messages.
The
format
uses
some

of
the
Baseline
TIFF
fields
in
addition
to
extensions
pertinent
to
facsimile
transmissions.
Since
the
format
can
be
used
over
both
traditional
and
host-
based
transmissions
media,
TIFF
-FX
is

suitable
as
a
downwardly
compatible,
standardized
facsimile
for-
mat
for
data
network communications. Profile S
(TIFF-S)
is
a
subset
of
TIFF,
related
to
TIFF-FX,
that
defines
a
minimal
black-and-white
format
to
enable
fast

easy
transmission
of
simple
facsimile
documents.
Profile
F
(TIFF-F)
is
a slightly
extended
version
of
Profile
S
that
is
still restricted
to
black-and-white
transmissions.
TIFF
-F
was
originally
introduced
by
Joe
Campbell

and
a
group
of
fax
experts;
then,
in
1998,
with
increased
interest
in
Internet
faxing
con-
nectivity,
it
was
formally
described
by
the
IETF
In-
ternet
Fax
Working
Group.
In

essence,
the
image
data
to
be
faxed
are
compressed
and
inserted
into
a
TIFF
-FX
file
with
the
informa-
tional
fields
encoded
with
data
specific
to
the
image.
The
byte

order
is
from
least
to
most
significant
(an
important
detail,
since
the
full
TIFF
specification
can
be
set
to
either
big-
or
little-endian
and
conversion
may
be
necessary
before
transmitting

as
a
TIFF-FX
variant).
While
the
full
TIFF
specification
is
some-
what
flexible
in
terms
of
the
ordering
and
structure
offields,
TIFF-FX
recommends
that
multiple
image
file
directories
(IFDs)
be

organized
as
a
linked
list.
The
MIME
Content
Type
for
these
files
is
image/tiff.
The
Application
parameter
is
TIFF
-REG
(optional).
See
IFax device, image file directory, TIFF,
RFC
2301,
RFC
2306.
TIIAP
See
Telecommunications

and
Information
Infrastructure
Assistance.
tiling
1.
In
printing,
a
technique
for
printing
a
large
image
on
pieces
of
paper
that
are
small,
relative
to
the
size
of
the
image.
Commonly

used
for
billboards,
banners,
and
wall-sized
murals.
Most
computer
print-
ers
have
options
for
tiling,
in
order
to
print
large
im-
ages
on
letter
sized
paper.
2. In
digital
image
display,

a
visual
artifact
common
to
heavily
compressed
im-
ages
which
causes
a
blocky,
mosaic-like
appearance
to
otherwise
smooth
lines
and
transitions.
See
DCT,
JPEG.
tilt locking A
method
of
frequency-locking
a
laser

beam
to
an
optical
cavity
by
misaligning
the
laser
with
respect
to
the
resonating
cavity
such
that
a
non-
resonant
spatial
mode
is
produced.
An
assessment
of
the
interference
between

the
carrier
and
the
spatial
mode
yields
a
quantum
noise-limited
frequency
dis-
criminator.
Tilt
locking
uses
interference
between
the
carrier
field
and
a
directly
reflected
phase
reference
signal (e.g., a non-resonant higher-order spatial
mode).
Thus,

the
encoding/decoding
of
spatial
modes
is
optical
rather
than
electro-optic.
Interference
between
the
two
spatial
modes
may
be
assessed
by
detecting
the
reflected
beam
on
a
two-
element
split photodiode
such

that
each
lobe
of a
transverse
electromagnetic
(TEM)
mode
is
incident
to
a
separate
side
of
the
photodiode.
The
error
signal
is
derived
by
subtracting
the
photocurrents
from
each
side
of

the
photodiode.
Tilt
locking
may
be
useful
for
frequency
stabilization,
conversion,
or
interferometric gravitational
wave
detection.
TIMA
See
Interactive
Media
Alliance,
The.
TIME
Time
Protocol.
A
network
date/time
protocol
submitted
as

an
RFC
in
May
1983
by
Postel
and
Harrenstien.
TIME
provides
a
site-independent,
ma-
chine-readable
date
and
time.
The
Time
service
pro-
vides
the
time
in
seconds
since
midnight
January

1,
1900.
This
is
useful
for
systems
that
do
not
have
a
built-in
date/time
clock
and
for
systems
that
need
to
be
coordinated
to
preserve
or
aid
data
integrity
or

pro-
cess
administration.
TIME
can
be
accessed
through
port
37
over
Transmission
Control
Protocol
(TCP)
or
over the User Datagram Protocol (UDP). See
RFC
868.
time
code
A
system
of
encoding
timing
information
on
a recording medium, usually along with the
information

that
is
being
stored.
This
technique
is
931
© 2003 by CRC Press LLC