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between the source and the destination, and the optical receiver can reliably decode the transmitted information. Other free-space systems can provide high-data-rate, long-range links using small, low-mass, low-power-consumption subsystems which make them suitable for communications in space. Various
260:
for conveying a message over long distances, but far more expensive and less private than the electrical telegraph lines which would later replace them. The maximum distance that a pair of semaphore telegraph stations can bridge is limited by geography, weather and the availability of light; thus, in
349:
The newer flag semaphore system uses two short poles with square flags, which a signaler holds in different positions to convey letters of the alphabet and numbers. The transmitter holds one pole in each hand, and extends each arm in one of eight possible directions. Except for in the rest position,
419:
have long used signal light guns to direct such aircraft. The light gun's lamp has a focused bright beam capable of emitting three different colors: red, white and green. These colors may be flashing or steady, and provide different instructions to aircraft in flight or on the ground (for example,
388:
Signal lamps (such as Aldis lamps), are visual signaling devices for optical communication (typically using Morse code). Modern signal lamps are a focused lamp which can produce a pulse of light. In large versions this pulse is achieved by opening and closing shutters mounted in front of the lamp,
493:
The heliograph was a simple but effective instrument for instantaneous optical communication over long distances during the late 19th and early 20th century. Its main uses were in military, surveys and forest protection work. They were standard issue in the
British and Australian armies until the
249:', or 'Napoleonic semaphore', is a system used for conveying information by means of visual signals, using towers with pivoting arms or shutters, also known as blades or paddles. Information is encoded by the position of the mechanical elements; it is read when the shutter is in a fixed position.
334:
Semaphore flags are the system for conveying information at a distance by means of visual signals with hand-held flags, rods, disks, paddles, or occasionally bare or gloved hands. Information is encoded by the position of the flags, objects or arms; it is read when they are in a fixed position.
632:
granted in Bell's name alone, and the 12 he shared with his collaborators, four were for the photophone, which Bell referred to as his "greatest achievement", telling a reporter shortly before his death that the photophone was "the greatest invention ever made, greater than the telephone".
96:, which reproduces the message from the received optical signal. When electronic equipment is not employed the 'receiver' is a person visually observing and interpreting a signal, which may be either simple (such as the presence of a
261:
practical use, most optical telegraphs used lines of relay stations to bridge longer distances. Each relay station would also require its complement of skilled operator-observers to convey messages back and forth across the line.
30:
396:
is tilted by a trigger to focus the light into pulses. The lamps are usually equipped with some form of optical sight, and are most commonly deployed on naval vessels and also used in airport control towers with coded
575:
The first optical communication systems were designed and delivered to the U.S. Army and
Chevron by Optelecom, Inc., the venture co-founded by Gordon Gould, the inventor of the optical amplifier and the laser.
1346:, Vol. 358, No. 1765, January 2000, Science into the Next Millennium: Young Scientists Give Their Visions of the Future: II. Mathematics, Physics and Engineering, pp. 303–329, stable article URL:
127:
use lasers to transmit signals in space, while terrestrial forms are naturally limited by geography and weather. This article provides a basic introduction to different forms of optical communication.
182:
sunlight to a distant observer. When a signaler tilts the mirror to reflect sunlight, the distant observer sees flashes of light that can be used to transmit a prearranged signaling code.
1386:
350:
the flags cannot overlap. The flags are colored differently based on whether the signals are sent by sea or by land. At sea, the flags are colored red and yellow (the
290:
with a network of 556 stations stretching a total distance of 4,800 kilometres (3,000 mi). It was used for military and national communications until the 1850s.
312:
These systems were popular in the late 18th to early 19th century but could not compete with the electrical telegraph, and went completely out of service by 1880.
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during night time. Only 12 simple standardized instructions are directed at aircraft using signal light guns as the system is not utilized with Morse code.
207:
use a similar system to land correctly on a carrier deck. The coloured light system communicates the aircraft's height relative to a standard landing
309:
developed his own system which was adopted by that state. This system was considered by many experts in Europe better than Chappe's, even in France.
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65:. The earliest basic forms of optical communication date back several millennia, while the earliest electrical device created to do so was the
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1070:, San Diego Evening Tribune, July 31, 1937. Retrieved from the University of San Diego History Department website, November 26, 2009.
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1718:
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Optical fiber is the most common type of channel for optical communications. The transmitters in optical fiber links are generally
420:"cleared to land" or "cleared for takeoff"). Pilots can acknowledge the instructions by wiggling their plane's wings, moving their
2497:
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On June 21, 1880, Bell's assistant transmitted a wireless voice telephone message of considerable distance, from the roof of the
565:
507:
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on
February 19, 1880, at Bell's 1325 'L' Street laboratory in Washington, D.C. Both were later to become full associates in the
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adopted systems of shuttered panels (in contradiction to the Chappe brothers' contention that angled rods are more visible). In
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was the real start of optical networking. WDM is now the common basis nearly every high-capacity optical system in the world
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2628:
502:
In the present day a variety of electronic systems optically transmit and receive information carried by pulses of light.
155:
were the earliest forms of optical communication. Hydraulic telegraph semaphores date back to the 4th century BCE Greece.
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First 'Radio' Built by San Diego
Resident Partner of Inventor of Telephone: Keeps Notebook of Experiences With Bell
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for inter-satellite links between the several hundred to thousand satellites effectively creating a space-based
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and are acceptable for emergency communication in daylight or, using lighted wands instead of flags, at night.
1361:, Toulouse: Institut National des Sciences Appliquées de Toulouse. Retrieved from IEEE Global History Network.
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systems which achieved popular worldwide usage starting in the 1980s. The master patent for the photophone (
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490:. The flashes are produced by momentarily pivoting the mirror, or by interrupting the beam with a shutter.
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1998:
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A 'semaphore telegraph', also called a 'semaphore line', 'optical telegraph', 'shutter telegraph chain', '
993:
Wavelength
Division Multiplexing: A Practical Engineering Guide (Wiley Series in Pure and Applied Optics)
2546:
2350:
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1946:
649:), was issued in December 1880, many decades before its principles came to have practical applications.
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271:, who first gave a vivid and comprehensive outline of visual telegraphy in a 1684 submission to the
203:(VASI) projected light systems to land safely, especially at night. Military aircraft landing on an
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holding a signal light gun that can be used to direct aircraft experiencing a radio failure (2007).
212:
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564:, which extended link distances at significantly lower cost. The commercial introduction of dense
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Many national services adopted signaling systems different from the Chappe system. For example,
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1154:, Sigma Xi, The Scientific Research Society, January–February 1984, Vol. 72, No. 1, pp. 66-71,
338:
Semaphores were adopted and widely used (with hand-held flags replacing the mechanical arms of
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1216:
Wilson, K. (2000-01-04). Recent
Development in High-Data Rate Optical Communications at JPL.
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The first operational optical semaphore line arrived in 1792, created by the French engineer
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The
Telegraph of Claude Chappe -An Optical Telecommunication Network For The XVIII Century
894:
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intended to provide global broadband coverage take advantage of these benefits and employ
17:
1968:
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848:. Retrieved on 1 June 2008. Note a discussion on the heliograph use during the Boer War.
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either via a manually operated pressure switch or, in later versions, automatically.
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38:, a form of optical communication that uses shutters and is typically employed with
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and can function over distances of several kilometers as long as there is a clear
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860:, Volume 17 of The Edinburgh encyclopaedia, pp. 664–667, 1832 David Brewster, ed.
789:
Communications: an international history of the formative years R. W. Burns, 2004
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to the window of Bell's laboratory, some 213 meters (about 700 ft) away.
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Philosophical
Transactions: Mathematical, Physical and Engineering Sciences
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1281:. Sterling Biographies. New York: Sterling Publishing Co., Inc. pp.
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342:) in the maritime world in the 19th century. They are still used during
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not equipped with a radio, or in the case of a hearing-impaired pilot.
358:). Flags are not required, they just make the characters more obvious.
275:. His proposal (which was motivated by military concerns following the
196:
81:
1226:
846:
Wire At War – Signals communication in the South
African War 1899–1902
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2765:
2087:
1879:
1832:
1414:
1038:
Laser: The
Inventor the Nobel Laureate and the Thirty-Year Patent War
1023:
Laser: The Inventor the Nobel Laureate and the Thirty-Year Patent War
1008:
Laser: The Inventor the Nobel Laureate and the Thirty-Year Patent War
695:
More generally, transmission of unguided optical signals is known as
629:
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cables are employed to carry electronic data and telephone traffic.
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the preceding year) was not put into practice during his lifetime.
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Heliograph: Australians using a heliograph in North Africa (1940).
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264:
The modern design of semaphores was first foreseen by the British
232:
116:
58:
29:
540:, because optical fibers transmit infrared wavelengths with less
330:
A naval signaler transmitting a message by flag semaphore (2002).
2732:
737:
186:
183:
107:
Modern communication relies on optical networking systems using
1836:
1585:
1368:
1318:, Information Gatekeepers, February 10–26, 1982, pp. 6–23.
219:
to transmit instructions to aircraft whose radios have failed.
100:) or complex (such as lights using color codes or flashed in a
61:
to carry information. It can be performed visually or by using
1978:
1775:
804:
Vol 10, Encyclopædia Britannica, 6th Edition, 1824 pp. 645-651
647:
Apparatus for Signalling and Communicating, called Photophone
1581:
494:
1960s, and were used by the Pakistani army as late as 1975.
294:
1108:, Melbourne, April 1987 pp. 12–17 and May 1987 pp. 13–17.
556:
have been demonstrated in the lab. The need for periodic
1340:
Future High-Capacity Optical Telecommunication Networks
1148:
Miller, Stewart E. "Lightwaves and Telecommunication",
92:, which carries the signal to its destination, and a
888:
An Early History of the Telephone: 1664-1865, Part 2
624:
Bell believed the photophone was his most important
590:
The photophone (originally given an alternate name,
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Advanced optical communication systems and networks
1274:
667:Free-space optics (FSO) systems are employed for '
594:) is a communication device which allowed for the
560:was largely superseded by the introduction of the
1255:Bell: Alexander Bell and the Conquest of Solitude
1192:"A 173-mile 2-way all-electronic optical contact"
913:"Fiber-Optic Technology Draws Record Stock Value"
510:are also used every day in various applications.
159:are still used by mariners in emergencies, while
1277:Alexander Graham Bell: Giving Voice To The World
424:if they are on the ground, or by flashing their
740:(OptoElectronics and Communications Conference)
354:), while on land, they are white and blue (the
797:
795:
1848:
1597:
1380:
1312:The First Century of Lightwave Communications
1172:Fiber-optic Communication Began 130 Years Ago
8:
1323:Encyclopedia of Laser Physics and Technology
901:, Institute For Learning Technologies, 2000.
486:(generally using Morse code) reflected by a
286:and his brothers, who succeeded in covering
167:are used to communicate navigation hazards.
2863:Global telecommunications regulation bodies
1135:Morgan, Tim J. "The Fiber Optic Backbone",
899:Columbia University in The City of New York
815:"Nation Park Service Fire History Timeline"
775:
773:
468:
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1180:, June 21, 2010. Accessed January 1, 2013.
976:: CS1 maint: location missing publisher (
552:, although historically optical phase and
548:. The signal encoding is typically simple
1225:
829:"Lewis and Clark Journals, July 20, 1805"
1096:
1094:
252:Semaphore lines were a precursor of the
769:
478:, meaning "write") is a wireless solar
991:Grobe, Klaus; Eiselt, Michael (2013).
969:
840:
838:
636:The photophone was a precursor to the
729:an inventor of optical communication.
699:(OWC). Examples include medium-range
7:
2909:
1348:https://www.jstor.org/stable/2666790
877:, 15 April 2000, Revised 4 May 2007.
871:The Origin of the Railway Semaphore
1040:. Jones Street Books. p. 283.
1025:. Jones Street Books. p. 212.
1010:. Jonas Street Books. p. 226.
123:, and other related technologies.
27:Use of light to convey information
25:
1325:, RP-Photonics.com website, 2012.
536:light is used more commonly than
508:Free-space optical communications
193:and Morse code in a similar way.
2908:
2898:
2889:
2888:
2877:
2498:Free-space optical communication
1817:
1807:
1565:
1556:
1555:
1190:Clint Turner (October 3, 2007).
995:. Wiley; 1st edition. p. 2.
659:Free-space optical communication
653:Free-space optical communication
614:, created and financed by Bell.
566:wavelength-division multiplexing
125:Free-space optical communication
1106:Wireless Institute of Australia
780:Chapter 2: Semaphore Signalling
697:optical wireless communications
663:Optical wireless communications
201:visual approach slope indicator
1:
602:. It was invented jointly by
344:underway replenishment at sea
2884:Telecommunication portal
2665:Telecommunications equipment
1814:Telecommunication portal
1248:, Cisco Press, Apr 23, 2004.
1104:, 'Amateur Radio' magazine,
911:Markoff, John (1997-03-03).
612:Volta Laboratory Association
562:erbium-doped fiber amplifier
256:. They were far faster than
2401:Alexander Stepanovich Popov
948:. Ivan Djordjevic. Boston.
701:visible light communication
482:that signals by flashes of
2956:
2105:Telecommunications history
1543:Modulating retro-reflector
1316:Fiber Optics Weekly Update
944:Cvijetic, Milorad (2013).
754:Parallel optical interface
733:Modulating retro-reflector
656:
583:
517:
447:
407:are used in the case of a
365:
319:
226:
135:Visual techniques such as
18:Optical data communication
2872:
2713:Public Switched Telephone
2525:telecommunication circuit
2486:Fiber-optic communication
2231:Francis Blake (telephone)
2026:Optical telecommunication
1804:
1689:Communications satellites
1551:
1517:Optical Transport Network
1396:Optical telecommunication
1273:Carson, Mary Kay (2007).
1218:Jet Propulsion Laboratory
1137:University of North Texas
638:fiber-optic communication
520:Fiber-optic communication
504:Fiber-optic communication
469:
459:
51:optical telecommunication
2624:Orbital angular-momentum
2061:Satellite communications
1900:Communications satellite
1259:Cornell University Press
1246:Fiber-Optic Technologies
1196:Modulated light web site
1177:San Antonio Express-News
682:satellite constellations
392:With hand held lamps, a
2503:Molecular communication
2326:Gardiner Greene Hubbard
2155:Undersea telegraph line
1890:Cable protection system
1684:Cable protection system
722:Interconnect bottleneck
707:, using infrared LEDs.
598:of speech on a beam of
417:Air traffic controllers
2935:Optical communications
2645:Communication protocol
2431:Charles Sumner Tainter
2246:Walter Houser Brattain
2191:Edwin Howard Armstrong
1999:Information revolution
1088:Carson 2007, pg. 76-78
608:Charles Sumner Tainter
445:
405:Aviation light signals
399:aviation light signals
385:
382:air traffic controller
372:Aviation light signals
331:
316:Semaphore signal flags
242:
213:airport control towers
43:
2619:Polarization-division
2351:Narinder Singh Kapany
2316:Erna Schneider Hoover
2236:Jagadish Chandra Bose
2216:Alexander Graham Bell
1947:online video platform
1824:Telephones portal
1036:Nick, Taylor (2019).
1021:Nick, Taylor (2019).
1006:Nick, Taylor (2019).
604:Alexander Graham Bell
526:light-emitting diodes
467:, meaning "sun", and
443:
379:
329:
307:Agustín de Betancourt
236:
47:Optical communication
33:
2461:Vladimir K. Zworykin
2421:Almon Brown Strowger
2391:Charles Grafton Page
2046:Prepaid mobile phone
1974:Electrical telegraph
1786:Telephone newspapers
1538:Intensity modulation
1321:Paschotta, Rüdiger.
1257:, Ithaca, New York:
1169:Mims III, Forrest M.
1102:Photophones Revisted
744:Optical interconnect
690:optical mesh network
554:frequency modulation
550:intensity modulation
254:electrical telegraph
241:tower (18th century)
145:hydraulic telegraphs
74:communication system
69:, invented in 1880.
57:at a distance using
2411:Johann Philipp Reis
2170:Wireless revolution
2132:The Telephone Cases
1989:Hydraulic telegraph
1709:Mobile phone signal
1420:Hydraulic telegraph
1079:Bruce 1990, pg. 338
1050:Bruce 1990, pg. 336
886:McVeigh, Daniel P.
703:and short-distance
686:laser communication
643:U.S. patent 235,199
558:signal regeneration
2940:Telecommunications
2609:Frequency-division
2586:Telephone exchange
2456:Charles Wheatstone
2386:Jun-ichi Nishizawa
2361:Innocenzo Manzetti
2296:Reginald Fessenden
2031:Optical telegraphy
1864:Telecommunications
1699:Free-space optical
1308:Mims III, Forest M
1167:Gallardo, Arturo;
1151:American Scientist
917:The New York Times
893:2012-11-28 at the
727:Jun-Ichi Nishizawa
673:telecommunications
606:and his assistant
446:
386:
340:shutter semaphores
332:
243:
113:optical amplifiers
80:, which encodes a
63:electronic devices
44:
2922:
2921:
2660:Store and forward
2655:Data transmission
2569:Network switching
2520:Transmission line
2366:Guglielmo Marconi
2331:Internet pioneers
2196:Mohamed M. Atalla
2165:Whistled language
1830:
1829:
1663:Answering machine
1579:
1578:
1430:Optical telegraph
1352:The Royal Society
1292:978-1-4027-3230-0
1126:Mims 1982, p. 14.
1117:Mims 1982, p. 11.
955:978-1-60807-556-0
875:Boston University
787:978-0-86341-327-8
568:(WDM) in 1996 by
430:navigation lights
165:navigation lights
16:(Redirected from
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2882:
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2753:Notable networks
2743:Wireless network
2683:Cellular network
2675:Types of network
2650:Computer network
2537:Network topology
2451:Thomas A. Watson
2306:Oliver Heaviside
2291:Philo Farnsworth
2266:Daniel Davis Jr.
2241:Charles Bourseul
2201:John Logie Baird
1910:Data compression
1905:Computer network
1857:
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1776:Fax transmission
1724:Submarine cables
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1485:Optical wireless
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975:
967:
941:
935:
934:
932:
931:
908:
902:
884:
878:
867:
861:
855:
849:
842:
833:
832:
825:
819:
818:
811:
805:
799:
790:
777:
645:
498:Electronic forms
472:
471:
461:
277:Battle of Vienna
247:Chappe telegraph
239:Chappe telegraph
205:aircraft carrier
84:into an optical
49:, also known as
21:
2955:
2954:
2950:
2949:
2948:
2946:
2945:
2944:
2925:
2924:
2923:
2918:
2878:
2876:
2868:
2810:
2747:
2669:
2633:
2590:
2539:
2531:
2472:
2465:
2371:Robert Metcalfe
2226:Tim Berners-Lee
2174:
1994:Information Age
1866:
1861:
1831:
1826:
1818:
1816:
1808:
1806:
1800:
1781:Telephone calls
1764:
1733:
1672:
1651:
1642:Satellite phone
1632:Cable telephony
1615:
1610:
1580:
1575:
1547:
1521:
1449:
1398:
1393:
1350:, published by
1333:
1331:Further reading
1328:
1293:
1272:
1252:Bruce, Robert V
1244:Alwayn, Vivek.
1240:
1235:
1215:
1214:
1210:
1200:
1198:
1189:
1188:
1184:
1166:
1162:
1147:
1143:
1134:
1130:
1125:
1121:
1116:
1112:
1099:
1092:
1087:
1083:
1078:
1074:
1059:Jones, Newell.
1058:
1054:
1049:
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1035:
1034:
1030:
1020:
1019:
1015:
1005:
1004:
1000:
990:
989:
985:
968:
956:
943:
942:
938:
929:
927:
910:
909:
905:
895:Wayback Machine
885:
881:
868:
864:
856:
852:
843:
836:
827:
826:
822:
813:
812:
808:
800:
793:
778:
771:
767:
762:
713:
665:
657:Main articles:
655:
641:
619:Franklin School
588:
582:
522:
516:
500:
452:
438:
374:
366:Main articles:
364:
324:
318:
305:, the engineer
237:A replica of a
231:
225:
197:Aircraft pilots
157:Distress flares
153:semaphore lines
133:
28:
23:
22:
15:
12:
11:
5:
2953:
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2943:
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2647:
2641:
2639:
2635:
2634:
2632:
2631:
2626:
2621:
2616:
2611:
2606:
2604:Space-division
2600:
2598:
2592:
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2589:
2588:
2583:
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2581:
2576:
2566:
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2564:
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2517:
2516:
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2505:
2500:
2495:
2494:
2493:
2483:
2477:
2475:
2467:
2466:
2464:
2463:
2458:
2453:
2448:
2443:
2441:Camille Tissot
2438:
2433:
2428:
2423:
2418:
2416:Claude Shannon
2413:
2408:
2406:Tivadar Puskás
2403:
2398:
2393:
2388:
2383:
2378:
2376:Antonio Meucci
2373:
2368:
2363:
2358:
2353:
2348:
2346:Charles K. Kao
2343:
2338:
2333:
2328:
2323:
2321:Harold Hopkins
2318:
2313:
2308:
2303:
2298:
2293:
2288:
2283:
2278:
2273:
2268:
2263:
2258:
2253:
2248:
2243:
2238:
2233:
2228:
2223:
2221:Emile Berliner
2218:
2213:
2208:
2203:
2198:
2193:
2188:
2182:
2180:
2176:
2175:
2173:
2172:
2167:
2162:
2160:Videotelephony
2157:
2152:
2151:
2150:
2145:
2135:
2128:
2123:
2117:
2112:
2107:
2102:
2097:
2096:
2095:
2090:
2085:
2075:
2074:
2073:
2063:
2058:
2056:Radiotelephone
2053:
2048:
2043:
2038:
2033:
2028:
2023:
2022:
2021:
2011:
2006:
2001:
1996:
1991:
1986:
1981:
1976:
1971:
1966:
1961:
1960:
1959:
1954:
1949:
1944:
1942:Internet video
1934:
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1876:
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1788:
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1778:
1772:
1770:
1766:
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1757:
1752:
1750:Misdialed call
1747:
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1400:
1399:
1394:
1392:
1391:
1384:
1377:
1369:
1363:
1362:
1355:
1337:Bayvel, Polina
1332:
1329:
1327:
1326:
1319:
1305:
1291:
1270:
1249:
1241:
1239:
1236:
1234:
1233:
1208:
1182:
1160:
1141:
1128:
1119:
1110:
1090:
1081:
1072:
1066:2006-09-04 at
1052:
1043:
1028:
1013:
998:
983:
954:
936:
903:
879:
869:Calvert, J.B.
862:
850:
834:
820:
806:
791:
768:
766:
763:
761:
758:
757:
756:
751:
746:
741:
735:
730:
724:
719:
712:
709:
654:
651:
584:Main article:
581:
578:
518:Main article:
515:
512:
499:
496:
454:A heliograph (
448:Main article:
437:
434:
394:concave mirror
363:
360:
322:Flag semaphore
320:Main article:
317:
314:
229:Semaphore line
227:Main article:
224:
223:Semaphore line
221:
132:
129:
26:
24:
14:
13:
10:
9:
6:
4:
3:
2:
2952:
2941:
2938:
2936:
2933:
2932:
2930:
2915:
2907:
2905:
2897:
2895:
2887:
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2823:
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2807:
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2799:
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2779:
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2774:
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2756:
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2731:
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2724:
2721:
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2716:
2714:
2711:
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2704:
2701:
2699:
2696:
2694:
2691:
2689:
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2684:
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2678:
2676:
2672:
2666:
2663:
2661:
2658:
2656:
2653:
2651:
2648:
2646:
2643:
2642:
2640:
2636:
2630:
2629:Code-division
2627:
2625:
2622:
2620:
2617:
2615:
2614:Time-division
2612:
2610:
2607:
2605:
2602:
2601:
2599:
2597:
2593:
2587:
2584:
2580:
2577:
2575:
2572:
2571:
2570:
2567:
2563:
2560:
2559:
2558:
2555:
2553:
2550:
2548:
2545:
2544:
2542:
2540:and switching
2538:
2534:
2526:
2523:
2522:
2521:
2518:
2514:
2511:
2510:
2509:
2506:
2504:
2501:
2499:
2496:
2492:
2491:optical fiber
2489:
2488:
2487:
2484:
2482:
2481:Coaxial cable
2479:
2478:
2476:
2474:
2468:
2462:
2459:
2457:
2454:
2452:
2449:
2447:
2444:
2442:
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2437:
2434:
2432:
2429:
2427:
2424:
2422:
2419:
2417:
2414:
2412:
2409:
2407:
2404:
2402:
2399:
2397:
2396:Radia Perlman
2394:
2392:
2389:
2387:
2384:
2382:
2379:
2377:
2374:
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2369:
2367:
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2334:
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2329:
2327:
2324:
2322:
2319:
2317:
2314:
2312:
2309:
2307:
2304:
2302:
2299:
2297:
2294:
2292:
2289:
2287:
2286:Lee de Forest
2284:
2282:
2281:Thomas Edison
2279:
2277:
2274:
2272:
2271:Donald Davies
2269:
2267:
2264:
2262:
2259:
2257:
2256:Claude Chappe
2254:
2252:
2249:
2247:
2244:
2242:
2239:
2237:
2234:
2232:
2229:
2227:
2224:
2222:
2219:
2217:
2214:
2212:
2209:
2207:
2204:
2202:
2199:
2197:
2194:
2192:
2189:
2187:
2184:
2183:
2181:
2177:
2171:
2168:
2166:
2163:
2161:
2158:
2156:
2153:
2149:
2146:
2144:
2141:
2140:
2139:
2136:
2134:
2133:
2129:
2127:
2124:
2121:
2118:
2116:
2113:
2111:
2108:
2106:
2103:
2101:
2100:Smoke signals
2098:
2094:
2091:
2089:
2086:
2084:
2081:
2080:
2079:
2078:Semiconductor
2076:
2072:
2069:
2068:
2067:
2064:
2062:
2059:
2057:
2054:
2052:
2049:
2047:
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2042:
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2037:
2034:
2032:
2029:
2027:
2024:
2020:
2017:
2016:
2015:
2012:
2010:
2007:
2005:
2002:
2000:
1997:
1995:
1992:
1990:
1987:
1985:
1982:
1980:
1977:
1975:
1972:
1970:
1967:
1965:
1962:
1958:
1955:
1953:
1950:
1948:
1945:
1943:
1940:
1939:
1938:
1937:Digital media
1935:
1931:
1928:
1926:
1923:
1921:
1918:
1916:
1913:
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1911:
1908:
1906:
1903:
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1784:
1782:
1779:
1777:
1774:
1773:
1771:
1767:
1761:
1758:
1756:
1755:Nuisance call
1753:
1751:
1748:
1746:
1743:
1742:
1740:
1736:
1730:
1727:
1725:
1722:
1720:
1717:
1715:
1712:
1710:
1707:
1705:
1702:
1700:
1697:
1695:
1694:Fibre-optical
1692:
1690:
1687:
1685:
1682:
1681:
1679:
1675:
1669:
1666:
1664:
1661:
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1607:
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1600:
1595:
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1554:
1553:
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1536:
1534:
1531:
1530:
1528:
1524:
1518:
1515:
1511:
1508:
1506:
1503:
1501:
1498:
1496:
1495:Visible light
1493:
1491:
1488:
1487:
1486:
1483:
1477:
1474:
1472:
1469:
1468:
1467:
1466:Optical fiber
1464:
1463:
1462:
1459:
1458:
1456:
1452:
1446:
1443:
1441:
1438:
1436:
1433:
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1428:
1426:
1423:
1421:
1418:
1416:
1413:
1411:
1408:
1407:
1405:
1401:
1397:
1390:
1385:
1383:
1378:
1376:
1371:
1370:
1367:
1360:
1357:Dilhac, J-M.
1356:
1353:
1349:
1345:
1341:
1338:
1335:
1334:
1330:
1324:
1320:
1317:
1313:
1309:
1306:
1302:
1298:
1294:
1288:
1284:
1279:
1278:
1271:
1268:
1267:0-8014-9691-8
1264:
1260:
1256:
1253:
1250:
1247:
1243:
1242:
1237:
1228:
1223:
1219:
1212:
1209:
1197:
1193:
1186:
1183:
1179:
1178:
1173:
1170:
1164:
1161:
1157:
1153:
1152:
1145:
1142:
1138:
1132:
1129:
1123:
1120:
1114:
1111:
1107:
1103:
1100:Groth, Mike.
1097:
1095:
1091:
1085:
1082:
1076:
1073:
1069:
1068:archive.today
1065:
1062:
1056:
1053:
1047:
1044:
1039:
1032:
1029:
1024:
1017:
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1009:
1002:
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987:
984:
979:
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947:
940:
937:
926:
922:
918:
914:
907:
904:
900:
896:
892:
889:
883:
880:
876:
872:
866:
863:
859:
854:
851:
847:
844:Harris, J.D.
841:
839:
835:
830:
824:
821:
816:
810:
807:
803:
798:
796:
792:
788:
784:
781:
776:
774:
770:
764:
759:
755:
752:
750:
749:Opto-isolator
747:
745:
742:
739:
736:
734:
731:
728:
725:
723:
720:
718:
717:Fiber tapping
715:
714:
710:
708:
706:
702:
698:
693:
691:
687:
683:
678:
677:line of sight
674:
670:
664:
660:
652:
650:
648:
644:
639:
634:
631:
627:
622:
620:
615:
613:
609:
605:
601:
597:
593:
587:
579:
577:
573:
571:
567:
563:
559:
555:
551:
547:
543:
539:
538:visible light
535:
531:
527:
521:
514:Optical fiber
513:
511:
509:
505:
497:
495:
491:
489:
485:
481:
477:
476:
466:
465:
457:
451:
442:
435:
433:
431:
427:
423:
418:
414:
410:
409:radio failure
406:
402:
400:
395:
390:
383:
378:
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369:
361:
359:
357:
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345:
341:
336:
328:
323:
315:
313:
310:
308:
304:
300:
296:
291:
289:
285:
284:Claude Chappe
280:
278:
274:
273:Royal Society
270:
267:
262:
259:
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250:
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240:
235:
230:
222:
220:
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188:
185:
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177:
173:
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158:
154:
150:
146:
142:
138:
137:smoke signals
130:
128:
126:
122:
118:
114:
110:
109:optical fiber
105:
103:
99:
95:
91:
87:
83:
79:
75:
70:
68:
64:
60:
56:
55:communication
52:
48:
41:
37:
32:
19:
2596:Multiplexing
2471:Transmission
2436:Nikola Tesla
2426:Henry Sutton
2381:Samuel Morse
2311:Robert Hooke
2276:Amos Dolbear
2211:John Bardeen
2130:
2110:Telautograph
2025:
2014:Mobile phone
1969:Edholm's law
1952:social media
1885:Broadcasting
1791:Théâtrophone
1769:Applications
1677:Connectivity
1637:Mobile phone
1526:Technologies
1461:Fiber-optics
1425:Ships' flags
1410:Smoke signal
1395:
1343:
1315:
1276:
1254:
1238:Bibliography
1217:
1211:
1199:. Retrieved
1195:
1185:
1175:
1163:
1149:
1144:
1131:
1122:
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882:
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809:
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666:
646:
635:
628:. Of the 18
623:
616:
596:transmission
589:
574:
530:laser diodes
523:
501:
492:
473:
462:
453:
403:
391:
387:
362:Signal lamps
348:
337:
333:
311:
292:
281:
269:Robert Hooke
263:
251:
244:
195:
191:signal lamps
169:
141:beacon fires
134:
131:Visual forms
119:, switches,
106:
71:
50:
46:
45:
2796:NPL network
2508:Radio waves
2446:Alfred Vail
2356:Hedy Lamarr
2341:Dawon Kahng
2301:Elisha Gray
2261:Yogen Dalal
2186:Nasir Ahmed
2120:Teleprinter
1984:Heliographs
1796:Video calls
1745:Missed call
1656:Accessories
1510:Consumer IR
1440:Signal lamp
542:attenuation
368:Signal lamp
352:Oscar flags
258:post riders
217:Aldis lamps
211:. As well,
161:lighthouses
104:sequence).
98:beacon fire
78:transmitter
72:An optical
36:signal lamp
2929:Categories
2842:Antarctica
2801:Toasternet
2723:Television
2206:Paul Baran
2138:Television
2122:(teletype)
2115:Telegraphy
2093:transistor
2071:Phryctoria
2041:Photophone
2019:Smartphone
2009:Mass media
1647:Photophone
1490:Free-space
1476:Connectors
1445:Photophone
1435:Heliograph
1227:2014/18156
1220:(Report).
930:2021-11-08
760:References
592:radiophone
586:Photophone
580:Photophone
570:Ciena Corp
546:dispersion
528:(LEDs) or
450:Heliograph
436:Heliograph
356:Papa flags
215:still use
209:glideslope
199:often use
189:often use
172:heliograph
149:ship flags
102:Morse code
67:photophone
40:Morse code
2826:Americas
2815:Locations
2786:Internet2
2547:Bandwidth
2251:Vint Cerf
2148:streaming
2126:Telephone
2066:Semaphore
1957:streaming
1760:Phone tag
1668:Caller ID
1613:Telephony
1301:182527281
972:cite book
964:875895386
925:0362-4331
858:Telegraph
802:Telegraph
765:Citations
669:last mile
626:invention
480:telegraph
2894:Category
2781:Internet
2771:CYCLADES
2688:Ethernet
2638:Concepts
2562:terminal
2513:wireless
2336:Bob Kahn
2179:Pioneers
2004:Internet
1895:Cable TV
1627:Landline
1561:Category
1533:OC Rates
1505:In space
1454:Advanced
1261:, 1990.
1201:June 28,
1064:Archived
891:Archived
711:See also
680:planned
534:Infrared
484:sunlight
475:graphein
422:ailerons
413:aircraft
266:polymath
94:receiver
34:A naval
2914:Commons
2904:Outline
2857:Oceania
2776:FidoNet
2761:ARPANET
2574:circuit
2143:digital
1872:History
1139:, 2011.
630:patents
470:γραφειν
426:landing
295:Britain
180:reflect
174:uses a
121:routers
90:channel
82:message
76:uses a
2852:Europe
2822:Africa
2806:Usenet
2766:BITNET
2703:Mobile
2579:packet
2088:MOSFET
2083:device
1880:Beacon
1571:Portal
1415:Beacon
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488:mirror
464:helios
299:Sweden
288:France
176:mirror
117:lasers
86:signal
42:(2002)
2835:South
2830:North
2791:JANET
2728:Telex
2718:Radio
2557:Nodes
2552:Links
2473:media
2051:Radio
2036:Pager
1964:Drums
1930:video
1925:image
1915:audio
1738:Calls
1620:Types
1500:Li-Fi
1471:Cable
1403:Basic
1285:–78.
600:light
460:Ἥλιος
456:Greek
411:, an
303:Spain
187:ships
184:Naval
59:light
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2847:Asia
2733:UUCP
2693:ISDN
1729:VoIP
1719:PSTN
1714:POTS
1704:ISDN
1297:OCLC
1287:ISBN
1263:ISBN
1203:2011
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960:OCLC
950:ISBN
921:ISSN
783:ISBN
738:OECC
705:IrDA
661:and
544:and
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297:and
170:The
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