Fiber Optics Illustrated Dictionary - Part 93 ppsx

A common architecture for building and managing communications services developed by the Telecommunications Information Network Ar-chitecture Consortium in the early 1990s.. Telecommunic

Fiber Optics Illustrated Dictionary

and suppliers of communications products for

mat-ters ofpublic policy and international commerce TIA

is accredited by the American National Standards

In-stitute (ANSI) to develop standards for a variety of

communication products See TIAFiber Optic

Com-munication Standards chart http://www.tiaonline.org/

Telecommunications InformationNetwork

Archi-tectureTINA A common architecture for building

and managing communications services developed

by the Telecommunications Information Network

Ar-chitecture Consortium in the early 1990s This

archi-tecture logically separates the physical infrastructure

and the applications from the need to communicate

directly with each another Control and management

functions are integrated and can be placed on the

net-work independent ofgeography through a single

Dis-tributed Processing Environment (DPE) See

Tele-communications Information Network Architecture

Consortium

Telecommunications Information Network

Ar-chitecture ConsortiumTINA-C An international

association ofover 40 telecommunications operators

and manufacturers who first came together at a TINA

Workshop in 1990 and formed the consortium to

cooperatively define a common architecture (TINA)

to be promoted as a global standard for building and managing telecommunications services This work draws heavily on the work ofother organizations and standards bodies in order to take advantage of ongo-ing studies and developments, to expedite the progress of the TINA project, and to promote the har-monious cooperation of various groups with similar goals http://www.tinac.com

telecommunications lines Physical lines, usually metal wire or fiber optic cable, over which commu-nications are transmitted, usually by electrical im-pulses or light Contrast to wireless communications

telecommunications main grounding bus bar TMGB.Animportant component of a telecommuni-cations electronic grounding system that extends the building grounding electrode system for a telecom-munications network infrastructure Typically one per building is housed in an accessible communications closet as a central attachment point for a telecommu-nications bonding backbone (TBB) with one or more telecommunications grounding busbars (TGBs) ATMGB is designed to facilitate low-resistance con-tact between lugs and busbars It should be directly bonded to the electrical service ground and to a TGB which, in tum, connects to a permanent metallic

TIA Fiber Optic Communication Standards

TWEIA-455-164A FOTP-I64

TIAlEIA-455-171A FOTP-171A

TWEIA-455-191A FOTP-191

FOTP-5 FOTP-78

100 Mbps

FOTP-87 FOTP-98 FOTP-157

Humidity Test Procedure for Fiber Optic Components Spectral Attenuation Cutback Measurement for Single-Mode Optical Fibers

Fiber Optic Cable Knot Test Fiber Optic Cable External Freezing Test Measurement of Polarization Dependent Loss (PDL) of Single-Mode Fiber Optic Components

Single-Mode Fiber, Measurment of Mode Field Diameter by Far-Field Scanning

Attenuation by Substitution Measurement for Short-Length Multimode Graded-Index and Single-Mode Optical Fiber Cable Assemblies Measurement of Mode Field Diameter of Single-Mode Optical Fiber Effective Transmitter Output Power Coupled into Single-Mode Fiber Optic Cable

Single-Mode Fiber Optic System Transmission Design Fiber Optic Connector Intermateability Standards Blank Detail Specification for Single-Mode Fiber Optic Branching Devices for Outside Plant Applications

Physical Layer Medium-Dependent Sublayer and 10 Mbps Auto-Negotiation on 850 om Fiber Optics

Relevant Technical Committees

TIAlEIA-455-87B

TWEIA-455-98A

TIAlEIA-455-157

TIAlEIA-455-5B

TIAlEIA-455-78A

TIA-559

TWEIA-604

TWEIA-620AAOO

TIAlEIA-785

FO-2.l Single Mode Optical Communication

Systems

FO-2.2 Digital Multimode Systems

FO-2.3 Optoelectronic Sources, Detectors, and

Devices

FO-2.6 Reliability of Fiber Optic Systems&

Active Optical Components

FO-6.1 Fiber Optic Field Tooling&Instrumentation

FO-6.2 FO-6.3 FO-6.6 FO-6.7 FO-6.9

Terminology, Defmitions,& Symbology Interconnecting Devices and Passive Products

Fibers and Materials Optical Cables Polarization-Maintaining Fibers, Connectors, and Components

never be bonded to a secondary electrical conduit or

pipe, as this may result in different ground potentials

between the TMGB and the communications

equip-ment grounding If multiple closets exist in the same

building; the TGBs should be bonded to one another

and to the TMGB through approved insulated wires

to form a TBB

The TMGB resembles a metal cribbage board in that

it has pairs of holes punched (all the way) through a

thin rectangular board and is supported by brackets

and insulators with noncorrosive fasteners The holes

are drilled according to recognized size and spacing

standards (e.g., NEMA) It is made of a conductive

material such as copper, and may be plated with

an-other metal such as nickel

TMGBs are generally designed to conform to ANSI!

TIA/EIA-607 specifications and BICSI

recommen-dations and come in a variety of widths and lengths

Once installed, TMGBs should be labeled with

warn-ings not to remove the structure or disconnect any of

its components

Telecommunications Management Network TMN

A global network management model for Network

Elements(NE)and Operation System (OS) and the

interconnections between them Global

standardiza-tion provides greater incentives for common interface

development Discussions of O&M aspects of

intel-ligent transmission terminals began, andTMN was

first formally defined in 1988, with the

recommen-dation for M.30 10 (Principles forTMN)published

in 1989, in addition to others over the next three years

OSI Management, originating in ISO, was adopted

as a framework forTMN to provide

transaction-ori-ented capabilities for operations, administration,

maintenance, and provisioning (OAM&P) Elements

of aTMN interface consist of various definitions,

models, and profiles, including architectural

defini-tion ofTMN entities, OAM&P functionality,

man-agement application and information models,

re-source information models, communication

proto-cols, conformance requirements, and profiles

Telecommunications Policy, Office of OTP

Agov-ernment agency, established in 1970 as an Executive

Office of the President during Richard M Nixon's

administration The OTP evolved from the 1968

President's Task Force on Telecommunications

Policy Clay T (Tom) Whitehead was the first OTP

Director Some of the staff were taken from the

ear-lier Office of Telecommunications Management

(OTM) The OTP was rolled into the U.S National

Telecommunications and Information Administration

in 1978 resulting from reorganization

Telecommunications Policy, President's Task

Force on Asignificant milestone in

telecommunica-tions policy development which came about partly

because of controversies regarding cable and long

distance services The Task Force was established in

1968 during the term ofPresident Lyndon B Johnson

Some ofthe important outcomes ofTask Force research

included the establishment of a government agency

to deal with telecommunications policy and increased

Telecommunications Policy Research Conference TPRCAnannual forum, first convened in 1972 as the OTP conference, for public and private sector scholars and decision-makers to discuss recent em-pirical and theoretical research and the needs of the telecommunications industry See Telecommunica-tions Policy, Office of http://www.tprc.org/

Telecommunications Reform ActAnact by the U.S

government opening up local and long distance mar-kets to competition The act included a highly con-troversial provision called the Communications De-cency Act (CDA) which was, after a great deal ofdis-cussion and input from the Internet community, de-clared unconstitutional The Reform Act significantly altered regulations ofthe telecommunications industry

Telecommunications Regulatory Email Grapevine TREG.Aninformal organization that carries on regu-lar online discussions about real world issues asso-ciated with taking products and services through the various regulatory processes This self-help, group an-swers queries and shares experiences, archiving the information on the Web

telecommunications relay service A 24-hour tele-phone service to assist hearing impaired individuals

to intercommunicate and to communicate with hear-ing subscribers This service may have a variety of telebraille, TTY, and voice options In general, the subscriber calls a telephone agent, who intercepts the call, translates it, and relays it to the callee on behalf ofthe caller The calls and call contentareconfidential

Telecommunications Research Establishment TRE A once-secret facility at Malvern where com-munications research such as radar research was con-ducted during World Warll.The TRE was established

in 1940, evolving from the Ministry ofAircraft Pro-duction Research Establishment (MAPRE) Some of the early research in digital storage devices was car- ' ried out here towards the end ofthe war Many ofthe ]~~. researchers at this facility made significant scientific achievements in a number of fields including radio astronomy See Small Scale Experimental Machine

telecommunications service This is defined in the Telecommunications Act of 1996 and published by the Federal Communications Commission (FCC), as

" the offering of telecommunications for a fee directly to the public, or to such classes of users

as to be effectively available directly to the pub-lic, regardless of the facilities used."

See Federal Communications Commission, Telecom-munications Act of 1996

Telecommunications Service Priority TSP Apro-gram of the Federal Communications Commission (FCC) for identifying and prioritizing telecommuni-cations services that support national security and/or emergency preparedness (NS/EP) missions The TSP regulates, administers, and operates priority restora-tion and provisioning ofqualified NS/EP telecommu-nications services to support emergency readiness and response to local, national, or international events or crises that might harm Americans or their property

http://tsp.ncs.gov/

Fiber Optics Illustrated Dictionary

Telecommunication Standardization Bureau TSB

The TSB provides support for the standardization

sector ofthe International Telecommunication Union

(ITU).Assuch, it helps to coordinate the work ofthe

lTU-T, provides secretarial services, assists in

dis-seminating information, and ensures the publication

of various references resulting from the work of the

lTU-T See International Telecommunication Union

Telecommunications Standards Advisory Council

of Canada TSACC A Canadian

industry-govern-ment alliance formed in 1991 to develop strategies

for Canadian and international standardization in

in-formation technology and telecommunications

Infor-mation on telecommunications technologies is

pro-vided on their Web site http://www.tsacc.ic.gc.ca/

Telecommunications Technology Association TTA

Established by the Korean Ministry of

Communica-tion in 1988, beginning operaCommunica-tions in 1992

http://www.tta.or.kr/

telecommuting Virtual commuting to the work site,

that is, communicating through various

telecommu-nications methods instead of physically traveling to

the work site A number of factors have contributed

to the increasing desire for, and availability of,

tele-commutingjobs: increasing congestion in cities

caus-ing higher houscaus-ing costs and less availability

ofhous-ing; increased traffic congestion; more families with

two working parents who don't want to leave

chil-dren unattended; improved telecommunications

ser-vices, with faster and better transmission, more

hookup services through phone lines, and

videocon-ferencing options

Telecommuting is not for everyone; many people

pre-fer to work under direction or to work in close

physi-cal proximity to co-workers, but many work better

undisturbed and will use the time saved by not

com-muting to produce a higher-quality product There are

also increasing numbers ofbusinesses willing to

pro-vide telework options so that they can recruit highly

skilled workers from diverse regions See telework,

virtual office

telecomputer, computerTV ATV broadcast

system-computer integrated system that allows a user to

con-trol program selection or menu options for viewing,

such as split screen for more than one show, digital

effects, sound options, integration of TV and phone

(e.g., on-screen Callerillon the TV when the phone

rings), email and Web access, shopping from home,

etc This is an example ofthe convergence ofthe

com-puter and broadcast industries Standards for ATM for

the home are being promoted so that standardized

commercial consumer systems can be developed

which allow these many technologies to link and

work together See Broadband Residential, fiber to

the home, Home Area Network, WebTV

teleconference A telephone conference where three

or more participants share in a conversation

Confer-ence call buttons or codes are available on some

lo-cal multiline systems, and operators can set up

con-ference calls across public lines for participants who

are distant from one another See videoconference

telecopier See facsimile machine

teledensity A measure of the number of telephone lines per 100 POPs (individual people) used to as-sess service distribution, economic compromises, revenues, etc

Teledesic, LLC A privately owned constellation of literally hundreds of satellites orbiting at 700km (LEO) designed to provide switched broadband bi-directional network services, including Internet ac-cess, data, voice, videoconferencing, and interactive multimedia It is designed to operate at up to 64 Mbps for downlink and up to 2 Mbps for uplink The top transmissions speed is more than 2000 times faster than standard modems operating over wired phone lines Connection is through small parabolic antennas The Teledesic group approached the Federal Com-munications Commission (FCC) in 1994 for a 500-MHz frequency allocation within the Ka-band for this service

In May 1998, Motorola Inc joined the venture as the prime contractor, bringing in its Celestri technology, along with Boeing Company and Matra Marconi Space, a European satellite manufacturer In August

2001, the company announced that either Lockheed Martin Commercial Space Systems (LMCSS) or Alenia Spazio (an Italian vendor) would be selected

as the prime contractor to build the network as both had experience in building nongeostationary-orbit satellite systems In November 2001, a talked about merger with another McCaw company, ICO Global Communications was discontinued In February

2002, an agreement was signed with Alenia Spazio

to contract the systems

Teledesic LLC is a McCaw/Gates company sched-uled to launch its satellites in the early 2000s and to

be in service by 2005

TeleDirectory A telephone directory service from British Telecom for personal computer users who have a frequent need for directory assistance services (e.g., five or more numbers per day) and wish to ac-cess the number online Enquiries are billed on a per-number basis See BT Phonebase

Telefunken AGerman radio station founded in 1903 soon after Marconi's wireless demonstrations in Lon-don, England, excited the imaginations of radio ex-perimenters and future broadcasters

telegaming Gaming over a distance communications medium (telephone, computer network, postal ser-vice) Telegaming has been around for a long time For centuries, people have played long distance chess and backgammon games by messenger and, more re-cently, by mail or phone Currently it implies an un-broken connection, since that is now possible through

computer networks and games like chess and go are

routinely played on the Internet Video arcade games are played on local networks, usually on an Ethernet link, although the term telegaming doesn't apply as well to an activity in which the participants can see

or hear one another in the same or next room telegenic Having characteristics that appeal to tele-vision audiences, such as charisma, talent, humor, relevance (news), or other qualities favored by broad-cast networks and viewing audiences

printed record ofa telegraphic communication Early

telegraph signals were transcribed on paper tape as

wiggly lines; later, audible signals were interpreted

by human operators and written down by hand; and,

finally, devices that could interpret the signals into

text and impress them on paper as telegrams were

devised For decades the telegram was delivered into

the hands of the intended receiver or at least brought

to the doorstep Courier services and facsimile

ma-chines are superseding telegram services See

tele-graph system, teletypewriter

telegraph fire alarmThat telegraph signals could be

used to report fires through signal boxes was realized

not long after the invention ofthe telegraph, and many

ofthe larger communities installed this type ofsafety

system by the early 1900s The Boston Fire Alarm

system was one of the first, following a published

description of its feasibility by William F Channing

in 1845 Later, with the help of a telegraph engineer,

Moses G Fanner, Channing supervised the 1851 city

funding and 1852 construction of the first fire alarm

telegraph in the world Originally based on manual

crank boxes, painted black, the mechanisms were

later changed to pull switches, and eventually dials

By 1881, the fire boxes were changed to red

telegraph historyThe telegraph was a system of

equipment and data encoding that enabled

commu-nication over distance, originally throughdrumbeats,

signal fires, and signal towers, and later by wires

pow-ered by high-intensity batteries As with many

tech-nologies, the telegraph was invented in a number of

places at about the same time, and many of the early

models were never practically or commercially

implemented

Ina sense, the technology has come full-circle Many

of the earliest modern telegraphs were optical

tele-graphs which gradually gave way to electrical

sys-tems and now, 200 years later, we are returning to the

use ofoptics, channeled automatically through fiber

rather than being transmitted by humans through air

Lesage had created africtional telegraph as early as

1774, and A Ampere and P Barlow proposed early

designs as well 1.Munro reports that someone

iden-tified only as C.M described an electric telegraph in

Scots Magazine in February 1753 that suggested a

multi-wire system (similar to those later implemented

by Campillo in Spain and Sommering in Germany)

Ifso, it is the earliest recorded reference to a modern

telegraph system Samuel T von Sommering created

a 35-wire telegraph based upon electrochemical

con-cepts which, inturn,was derived from the work of

Francesc Salva i Campillo in Spain, in 1795

Optical telegraphs were developed by Claude and

Ignace Chappe in the early 1790s and were probably

built upon the ancient tradition of signal fires The

Chappe system used physically coded letters and

symbols relayed through a system of towers by

hu-man "transceivers." The concept spread to other parts

of Europe, including Denmark, where an optical

postal telegraph was established in 1801

One ofthe first practical commercial implementations

stone and W Cooke in England The telegraph in America owed much of its design and development

to Samuel Morse and Alfred Vail Morse's original telegraph caveat (an intention to file a patent) de-scribed a mechanism with a horizontally moved key which made corresponding zigzag marks on a mov-ing paper tape to represent numbers, which were then looked up to find the corresponding words in a refer-ence dictionary prepared by Morse Vail improved on the mechanics of the key, making it move up and down instead of side-to-side, thus forming dots and dashes with breaks in between on the paper As this system was simpler and more direct than doing a dic-tionary lookup, it evolved into the system now known

as Morse (Vail) code Their telegraphic invention was demonstrated to the Presidency in 1838 Morse sub-sequently won funding from Congress to construct a telegraph long distance line, carried out the project with assistance from Ezra Cornell, and began to spread telegraphy throughout America in the mid-1800s Both Wheatstone and Morse received advice and encouragement on the development of tele-graphic instruments from Joseph Henry in the 1830s Morse, unfortunately, didn't duly credit Henry's as-sistance

Historic Telegraph Communications Technology

One of the early Bell telegraph patent documents There were many inventors at the time independently making similar discoveries, and substantial competi-tion to be the first to patent and commercialize the new communication technologies.

Inits simplest form, the telegraph consists ofa sender (a keying device), a receiver (with a sounder or printer), and a simple code for conveying characters Early telegraph receiving machines used paper tapes

to record messages (Morse's telegraph created a wig-gly line), but operators began to recognize the slightly audible incoming clicks and could copy messages faster than a paper tape could print them, so machines

were soon equipped with sounders and resonators to

amplify and direct these clicks Not surprisingly,

Fiber Optics Illustrated Dictionary

many inventors sought waystotranslate the signals

into letters that could be recorded directly, as in a

tele-gram or teletype-style printout One of the first to

succeed was David Hughes, a schoolteacher, in 1856

In America, messages were sent by shutting current

on and off, while in Britain, Wheatstone introduced

polar keying,a means ofusing polarity to convey

sig-nals The concept of polarity is still used today in

high-speed data transmissions

In1866, M Loomis demonstrated that signals could

be sent from one airborne kite to another, when each

was strung with fine copper wire of the same length,

without direct physical contact This later lead to his

1872 U.S patent for a wireless improved telegraphic

system, although it was some time before his discoveries

were put into practical use

By the 1880s, scientific investigations and

demon-strations had confirmed the viability of wired and

wireless telegraphy The end of the century then

be-came a time of creative application of the concepts

and evolutionary improvements in speed and

practi-cality

In 1895 and 1896, in Russia, A.S Popow was

con-ducting experiments with wireless telegraphy and

succeeded in sending a shipboard message to his

labo-ratory in St Petersburg Unfortunately, due to the

se-crecy surrounding Russian naval technology and

in-ventions in general, Popow's discoveries were not

communicated to the rest of the world, and he did not

receive credit for his early experiments

Inthe late 1800s, telautographs that could transcribe

handwriting were created by several inventors such

as E Gray and F Ritchie While these were used for

several decades, they didn't originally work over long

transmission lines and were superseded by telewriters

and, eventually, facsimile machines

In 1886, Amos Dolbear, a Tufts University scientist

and writer, was awarded a patent for a wireless

tele-graph based on induction

In1889, EG Creed invented a High Speed Automatic

Printing Telegraph System By 1898, his Creed

Printer could transmit 60 words per minute and his

technology was widely sold in many countries He

broadened.his enterprise in 1923 by demonstrating

marine wireless printed telegraphy, a system

even-tually used for marine safety

Wireless telegraphy was of interest almost from the

beginning of telegraphic history In the early 1900s,

V Poulsen and P Pedersen used an electric arc to

generate high-frequency waves, setting the

ground-work for wireless communications Poulsen also

de-veloped the telegrafon, a historic electromagnetic

tape recorder Tape recorders were later used to

de-velop dictation and telephone answering machines

The telegraph had a revolutionary impact on

commu-nications, changing forever the concept of distance

It networked the predominantly rural early settlers of

North America and spurred the installation ofthe first

transatlantic cable, providing instant (by l800s

stan-dards) communication with Europe Prior to the

oce-anic cable, messages typically took 2 months or

longer to travel in ships from one continent to the

other News, business, warfare, and family contacts were dramatically affected by the availability offast long distance communications

See Creed, Frederick George; heliotrope; Davy, Ed-ward; Dolbear, Amos; Morse, Samuel F.B.; Popow, Aleksandr Stepanowitsch; Salva i Campillo, Francesc; S6mmering, Samuel Thomas; Steinheil, Karl August; telegram; telegraph system; telephone; Wheatstone, Charles

telegraph key A mechanical switch on early

tele-graph systems that enabled a circuit to be opened and closed in order to generate transmissions through a signal such as Morse code

telegraph signals For telegraph signals through

wires, two main methods were used: polar

transmis-sion, in which the polarity was changed to reverse the

current; and neutral, or open/close transmission, in

which open current (space) was interspersed with no current (mark)

telegraph systemAnapparatus for sending and/or receiving information over distance, coded in some fashion, usually in Morse code dots and dashes A basic telegraph circuit consists of a key to translate finger or other mechanical pressure into signals, a relay sensitive to the very small current that may be coming through the wire, and a receiving device which can express the message by means of audible tones, paper tape code, or printed letters

Telegraph systems have coexisted with, rather than been superseded by, telephone systems for a number

of reasons, including the expense and time delays of setting up long distance toll calls to some areas, and the importance, in some situations, of creating a writ-ten record in the form of a telegram With electronic telephony advancing and facsimile machines prolif-erating, the telegraph is becoming more historically interesting than practical See telegraph history; tele-graph, needle

Telegraph Network System

A telegraph network map ofthe United States pub-lished ca 1870 which shows the Pony Express Mail

& Telegraph Route (in spite ofthe fact that the Pony Express was velY shortlived).

telegraph, needle A type of five-needle telegraph

devised by Charles Wheatstone and put into service

in England in 1837 Faulty equipment lead to the

needles were sufficient and, eventually, only one

needle and one dial were used to efficiently convey

messages The needle telegraph also represents the

development ofpolar keying, which employed

posi-tive and negaposi-tive voltages for indicating mark and

spacesignals See polar keying

telegraph, printingEarly telegraph papertape and

manually operated sounding systems did not satisfy

the needs of inventors and users who wanted quick,

automated written messages Thus, the development

of printing telegraphs was of interest to many One

of the first successful systems was developed by

A Vail in 1837, employing a type wheel Later D

Hughes developed a practical working type wheel

system in 1855, which became established in Europe,

but didn't catch on well in America, where Morse

systems were in use Improvements to printing

tele-graphs continued and, in 1846, R.E House developed

a printer that printed telegraphically transmitted

let-ters directly Further improvements to House's

sys-tem resulted in a patent in 1852 In 1905, Donald

Murray published "Setting Type by Telegraph" in the

Journal ofthe Institute ofElectrical Engineers and

went on to improve telegraphy in a number ofways

The necessity of noise-free transmissions and

tech-nical expertise to maintain the equipment prevented

printing telegraphs from coming into widespread use

until decades later See teletypewriter

Historic Automatic Telegraph System

An automatic telegraph sender The wheels shown

at the top represented characters that could be selected

and placed in order to spell out a message This

ex-ample is from the American Radio Museum

collec-tion.

telegrapheseA terse, abbreviated mode of

messag-ing (or speakmessag-ing) which has the character of a

tele-gram Since telegrams were often charged by the

let-ter or by the word, a compact style of

communica-tion emerged in order to keep the cost as low as

prac-tical

telegraphone, telegrafonThis is not only a type of

telegraph instrument, but more important, was an

early electromagnetic tape recorder, designed in 1898

by Danish inventor Valdemar Poulsen Poulsen

suc-ceeded in recording electronic waves on a thin wire

receive a u.S patent in 1890 This developed into dictating machines sold through the American Tele-graphone Company See tape recorder

TeleLink ProjectThe full name is TeleLink Train-ing For Europe Project This is a European Commu-nity (EC), Euroform-funded project which seeks to promote and develop telework training opportunities and qualification guidelines This includes qualifica-tion level certificaqualifica-tion (currently at the vocaqualifica-tional level) for teleworkers and a system of TeleLink cen-ters around Europe See ADVANCE Project, tele-work

telemarketingThe promotion of products and ser-vices through telephone calls to individual premises There are various regulations governing when tele-marketers may call, whom they may call (e.g., calls

to a person at his or her place of business must be stopped if the callee requests it), and what they must say to identify themselves and their affiliations There are also restrictions on where they may obtain names, and how they must dial the call Many scams have been perpetrated through telemarketing schemes, and

it is important for the callee to get sufficient infor-mation to ascertain that the offering is legitimate If you don't wish further calls from the source, you should request that your name be taken off their list See war dialer

telemarketing broadcastsThe promotion of prod-ucts and services through mass market advertising usually providing a 1-800 or 1-900 number for the interested buyer to call Automated systems for tak-ing the caller's name and billtak-ing information through touchtone selections are becoming prevalent telemedicineMedical information and services and medical education provided over distance through telephone, radio, facsimile, videoconferencing, and the Internet Information such as medical imaging results can readily be transferred as data, since much

of it is digital in nature Teaching and other commu-nications among medical professionals and their pa-tients are possible through newer technologies telemetry, telemeteringThe art and science ofgath-ering information at one location, usually in terms of some quantity, and transmitting that information to another location for storage, analysis, or evaluation Weather balloon data gathering and transmission through a radiosonde to a weather station for inter-pretation is one example of telemetry The transmit-ting ofinformation from space probes is another Te-lemetry equipment is typically included on artificial satellites to aid in the control and orientation of the satellites

TeletextA commercial computer service offered by NBC, which was discontinued in 1985 Many ofthese early computer services came and went, but they are coming back in updated forms now that there is a large user base drawn to the Web

telephoneA communications apparatus designed primarily to convey human voice communications

In its simplest form, a telephone consists of a tran-sistor that converts sound into electrical impulses, and

Fiber Optics Illustrated Dictionary

a receiver, which converts them back again into

sound Additional technology is used to amplify and

direct the communication between these two basic

de-vices The design of the telephone set has gone

through five overlapping phases in its development

See the Telephone Development Phases chart See

telephone history

Historic Telephone

The earliest telephone was a simple device that

looked more like a pinhole camera than current

fa-miliar desktop phones and mobile handset phones.

telephone amplifier A device to amplify sounds at

the receiving end of a call This can be incorporated

into the handset, headset, or speakerphone, or may

be an add-on to provide even more amplification for

the hard ofhearing Most handset telephone

amplifi-ers draw current from the phone line, but many

speakerphones and add-on amplifiers require a

sepa-rate power source The amplifier is often adjustable

through a dial or slider on the side of the phone

telephone answering machine An electronic or

me-chanical device for answering calls and often for

re-cording them digitally or on tape Telephone

answer-ing machines based on reel-to-reel mechanisms have

been available since the early 1960s, but small

cas-sette and digital answering machines did not become

common until the late 1970s and early 1980s

Most households now have answering machines to

respond to calls, take messages, or screen calls Many

ofthese will include information on the time and date

of the call, and some will record the identity of the

caller, ifCallerillis activated on the subscriber line

Computer voicemail applications can also be hooked

to a phone line through a data/fax/voice modem to

allow the software to function as a full-featured

an-swering machine with multiple mailboxes

telephone answering service 1 Aservice offered by

commercial vendors in which a human operator or

voice-automated system will answer the subscriber's

phone line when it is call fOIWarded, or when the

an-swering service number is called directly and

for-wards the message to the subscriber This service is

widely used by small businesses, freelancers, and real

estate agents Sometimes these services are combined

with paging 2 Aservice offered by local phone

com-panies in which a human operator or voice-automated

system will take calls and fOIWard messages to the subscriber, or through which the subscriber can use

a touchtone phone to retrieve messages

telephone central office See central office telephone circuit An electrical connection consist-ing minimally ofa transmitter, receiver, amplifier, and connecting wires, and more commonly comprising

a system oftwo-way audio and signaling connections between local exchanges and subscriber lines and telephones

Telephone Company of Prince Edward Island A historic telephone exchange, incorporated in 1885, the year after the phone exchange was first established

on the island

telephone exchange Switching center for telephone circuits See central office, private branch exchange

Innovative Optical Telephone

An innovative optic telephone, based on the stimu-lation through a diaphragm ofa flame from an acety-lene burner The impulses were then further

and reflector The optic telephone was developed by Ernst Ruhmer, and was used for long distance

1902.}

telephone history The telephone was a significant evolutionary development, occurring a few decades after the invention of the telegraph While the tele-graph revolutionized telecommunications by making communications over great distances possible, the telephone personalized it, and many inventors were excited by the potential of sending tones, or even voice, over phone lines

The use of tubes and strings to magnify sound and channel acoustic vibrations existed at least as early

as the time of Robert Hooke, long before the devel-opment of modem telephones, but such devices, like the acoustic tubes demonstrated in 1682 by Dom Gauthey, were physically limited as to loudness and distance It was not until electricity and magnetism were harnessed that amplified, long-distance modem telephony was possible

In the early 1800s, German inventor Philip Reis ob-served that a magnetized iron bar could be made to

discovery, terming the sound "galvanic music."

Sub-sequently, a number of inventors advanced

tele-graphic and microphonic technologies leading up to

the invention of the telephone Belgian inventor

Charles Bourseul described his idea for transmitting

tones in 1854, but wasn't able to implement a fully

working version before Philip Reis and Alexander

Graham Bell developed their own telephonic devices

Reis first demonstrated the transmission of tones

through wire in Frankfurt in 1861 He reported in a

letter that he could transmit words, but there is no

direct way to verify the claim

Around the time ofReis's death, an American

physi-cist, Elisha Gray, was making numerous experiments

in telegraphy and developed early concepts for

har-monic telegraphy, the transmission of tones, and

te-lephony

In the mid-1800s, Italian-born Antonia Meucci was

successfully experimenting with wires attached to

animal membranes to transfer sound through current,

but news ofhis significant discoveries did not become

widely known outside Cuba When he later emigrated

to the U.S., he filed a caveat for a patent, in

Decem-ber 1871, for ateletrofono.

Bell's Telephone Demonstration

Here Alexander Graham Bell demonstrates his

tele-phone invention The inset shows one of his early

sketches ofthe invention, from the famous Bell

note-books Bell achievedgreatfinancial successfrom

com-mercializing his discoveries.

The better-known precursors to the telephone in

America and later variations appear to have been

in-vented more-or-Iess independently by Elisha Gray

and Alexander Graham Bell, but Bell filed his

phone patent (it was actually a precursor to the

tele-phone, a hannonic telegraph) a few hours before Gray

filed a caveat (intention to file within 3 months) in

February 1876 The murky history of the invention

of the telephone at this point stems in part from the

fact that many innovationswere being developed

si-multaneously and also because the inventors

under-stood the great commercial potential oftheir devices

Hundreds of lawsuits were threatened and filed over

more amicably settled For example, in January 1877, Bell wrote to Gray rescinding any previous accusa-tions he may have made that Gray copied from Bell's work.(Infact, both men may have copied from a third source, Antonia Meucci It has been suggested, but not confirmed, that both Bell and Gray had access to Meucci'steletrofono documents when they were in

the hands ofWestern Union.) Emil Berliner was an inventor with a strong interest

in music and the improvement of the quality of transmission of sound (which applied equally well

to telephony).InApril 1877, he filed a caveat for a patent for a telephone transmitter, three and a half months before Thomas Edison applied for a patent for a similar device

Ina 1911 lecture on the origins ofthe membrane tele-phone, Bell described how he worked out the idea in discussions with his father while on a family visit in Canada in the summer of 1874,2 years before it was successfully implemented Bell and Watson reported that Bell first spoke intelligibly over wires in March

1876 The transmission succeeded by use of a liquid medium, something not mentioned in Bell's patent This voice capability was not publicly demonstrated until some time later, which seems odd given the magnitude of the reported achievement Ironically, Bell had been discouraged by investors from trying

to make a talking telegraph and was prodded to con-centrate on a harmonic telegraph instead

Gray had publicly demonstrated rudimentary tele-phone-related technology before the Bell patent was filed, and later successfully earned a number oftele-phone-related patents He designed a telephone in the 1870s not unlike the second-generation switch-hook phones that employed separate ear and mouth pieces which came into use in later years

The first commercial telephone exchange was estab-lished in Connecticut, U.S., and became operational

in 1878 It was followed the same year by the second commercial exchange in Ontario, Canada

The Bell patents formed the basis of the early Bell System in the United States, a company that has in-fluenced the development of communications, and thus the course of history, in countless important ways The Bell Telephone Company of Canada was incorporated in 1880

By this time, telephone technology began to spread

to other nations outside Europe and North America The first telephone exchange was established in Ja-pan in 1890 in the TokyoNokohama region.In1926, automatic step-by-step switches were introduced in Japan

The most interesting evolutionary step in telephone technology, besides the growth of wireless commu-nications, is probably the videophone, descended from early picture telephones such as the Picture-phone The Bell Labs were transmitting pictures in the late 1920s and demonstrated the early technol-ogy to the Institute of Radio Engineers in 1956, but

it was not until 1964 that a practical experimental system was completed and the Picturephone was

Fiber Optics Illustrated Dictionary

exhibited cooperatively by Bell and the American

Telephone and Telegraph Company (AT&T) at the

New York World's Fair

Currently many companies are scrambling to be the

first to get a cheap, publicly accepted version of a

pic-ture telephone or as they are known now,

audiograph-ics systems, videophones, or videoconferencing

sys-tems With the growth of the Internet and the drop in

price of small video cameras, they began to be

com-mon computer peripherals in 2002

Another significant change in telephony has been the

sending of voice over computer networks by means

of a specialized handset attached to a computer This

permits the connection of long distance calls world

round without any long distance toll fees The

tech-nology threatens to dramatically change the

estab-lished economic structure of the telephone system,

and it is difficult to predict whether the same

revenue-generating model that has worked for about 100 years

will be viable in the future, given the current rate of

change In fact, some of the long distance carriers,

worried by this threat to their survival, have lobbied

for this type of transmission to be blocked See Bell,

Alexander Graham; Berliner, Emil; Bourseul,

Charles; Callender switch; Gray, Elisha; Meucci,

Antonio; Photophone; Reis, Philip See telegraph

his-tory which has acommon ancestry and additional details

telephone landline density A measure of the

num-ber of installed phone lines per 100 people

telephone pickup Any of several devices for

con-necting into an ongoing telephone conversation,

usu-ally for monitoring purposes

Telephone Pioneers of America TPA A nonprofit

organization founded in 1911, with chapters

through-out the United States and Canada Originally

consist-ing of telephone pioneers with 25 years of service or

more, with Theodore N Vail as its first president,

membership later opened up to a wider group, now numbering almost 100,000, as fewer pioneers re-mained from the original group

TPA engages in a number of community-oriented activities, with a particular focus on education A somewhat analogous organization serving non-Bell employees is the Independent Pioneers

http://www.telephone-pioneers.org/

telephone receiver The portion of a handset, head-set, or speakerphone which converts electrical impulses into sound On a handset, the receiver is the part that you hold up to your ear Inside a basic tradi-tional receiver is a magnet, with coils wound around the poles connected in series and a light, thin, vibrat-ing diaphragm mounted very close to the magnet poles When current passes through the coils, the dia-phragm vibrates, producing sound by moving the air next to it Early receivers used a bar magnet, which later was replaced by a horseshoe magnet See tele-phone transmitter

Telephone Relay Service A telephone service en-abling handicapped individuals to communicate over telephones through third party interpreters It is usu-ally provided free of charge

telephone repeater An amplification device em-ployed on telephone circuits to rebuild and maintain signals across distances, which otherwise would be subject to loss

telephone signaling Any device that indicates an in-coming call, usually a bell, but may also be a light or moving indicator

telephone switchboard A centralized distribution point for managing telephone calls Early switch-boards consisted ofa human operator answering calls, and plugging a large physical jack into the receptacle

of the person to whom the call was being patched The first commercial switchboard in North America

Overview of Telephone Development Phases

original invention late l800s Proof of concept, tbe first discernible, intelligible buman

voices can be heard over distances

hand crank pbones late 1800s, early 1900s Pbones were large, to accommodate a battery, and had to

be cranked to send a ringing current Hand-crank phones were still in use in rural areas, including some of the San Juan Islands in the 1960s

dial phones early 1900s to 1980s Common batteries and automatic switching systems made

it possible to create smaller, line-powered phones and rotary dials so the subscriber could direct dial a local call, and later, long-distance calls

touchtone phones late 1970s to present Phones that sent tones rather than pulses through the line,

which were interpreted according to pitch This made automated menu-controlled systems possible

digital phones early 1990s to present Interface speakers or beadset peripherals that attach

directly to a computing device or desktop system to enable the user to talk into a digitizing program that samples the sound and transmits it over public data networks

Semiautomatic Telephone Switching System

were mechanized in the mid-1900s, although it was

not uncommon for human switchboard operators to

staff manual switchboards in rural areas and private

branches until the 1950s Although mechanical

switchin~ stations still exist, updated switchboards

function electronically

telephone tag Colloquial phrase for two parties

at-tempting to contact one another by phone, not reaching

the other person, and leaving messages with an

answering machine, operator, or voice mail system

Doing this back and forth a few times is telephone tag

telephone transmitter The portion of a handset,

headset, or speakerphone which converts sound into

electrical impulses On a traditional handset, the

re-ceiver circuit connects to the part that you hold next

to your mouth Inside the mouthpiece is a movable

diaphragm with an attached carbon electrode, behind

which another carbon electrode is fastened securely

inside the housing Between the electrodes are

car-bon granules (it's possible to build a simple phone

transmitter using the core of a carbon pencil laid

across two conducting surfaces connected to wires

and a diaphragm) When a current is applied,

resis-tance decreases, as a result of the carbon granules

compressing more closely together Thus the current

increases and attracts the diaphragm more strongly

The diaphragm vibrates to produce an electrical

im-pulse that corresponds to the movement ofair caused

by the speaker's voice.Aninduction coil may also

be used to increase the voltage to compensate for

sig-nalloss through the transmissions medium See Blake

transmitter, coherer, telephone, telephone receiver

telephone user interface TUI The use of telephone

equipment, usually a handset or headset or telephone

line attached to a peripheral card, to interact with

computer software Instead of using a keyboard and

mouse as the input devices, voice or touchtones over

tions of the computer For example, you may have a computer set up like an answering machine to answer calls, respond to callers, and log time, date, and caller messages Then, from aremote location, you may call the line attached to the computer, and by speaking or pressing touchtone buttons, have the computer send back information about the calls or replay the calls telephony The science and practice of transmitting audio communications over distance, that is, over a greater distance than these communications could be transmitted without technological aid The term has broadened from audio communications to encompass

a wide variety of media, typically now including

vi-sual communications that accompany sound commu-nications (as in audiographics and videoconferenc-ing), although it is preferred that the more general termtelecommunication be used for audio/visual

transmissions Most telephony occurs over wires, but wireless services transmitted by radio waves and sat-ellite links are increasing I

Telephony, in its simplest sense, is not a high band-width application; each conversation requires only a narrow channel, but because of its continuous bidi-rectional nature, bandwidth needs increase as the number of simultaneous calls increases Traditional telephony media, such as copper wires, are no longer strictly used for oral communications; they now ser-vice a large number ofdata transmission serser-vices such

as Internet connectivity, facsimile transmission, and more Due to increased demands for lines with greater speed and accuracy than are needed for simple voice transmissions, fiber and coaxial technologies are be-ing used to upgrade data lines and, consequently, the phone lines See HFC, telephone, telegraph Telephony Application Interface TAP! Astandard-ized telephone interface developed by Microsoft and Intel Corporation for the creation of a variety of

A schematic for a historic semiautomatic telephone switching system (it still required a human operator to turn a spring-loaded knob to send the dial pulses through the wire) [Scientific American, October11,1902.]