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404:
163:
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151:
31:
428:
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issues a lifetime commercial
Radiotelegraph Operator License. This requires passing a simple written test on regulations, a more complex written exam on technology, and demonstrating Morse reception at 20 words per minute plain language and 16 wpm code groups. (Credit is given for amateur extra class
825:
in 1932. When the United States entered World War I, private radiotelegraphy stations were prohibited, which put an end to several pioneers' work in this field. By the 1920s, there was a worldwide network of commercial and government radiotelegraphic stations, plus extensive use of radiotelegraphy by
339:
made in 2021. Since 2003, knowledge of Morse code and wireless telegraphy has no longer been required to obtain an amateur radio license in many countries, it is, however, still required in some countries to obtain a licence of a different class. As of 2021, licence Class A in
Belarus and Estonia, or
593:
of constant amplitude. Since all the radio wave's energy was concentrated at a single frequency, CW transmitters could transmit further with a given power, and also caused virtually no interference to transmissions on adjacent frequencies. The first transmitters able to produce continuous wave were
902:
486:
linking distant stations was very expensive, and wires could not reach some locations such as ships at sea. Inventors realized if a way could be found to send electrical impulses of Morse code between separate points without a connecting wire, it could revolutionize communications.
518:
and thus fell under the Post Office monopoly. This did not seem to hold back
Marconi. After Marconi sent wireless telegraphic signals across the Atlantic Ocean in 1901, the system began being used for regular communication including ship-to-shore and ship-to-ship communication.
69:
was also used for other experimental technologies for transmitting telegraph signals without wires. In radiotelegraphy, information is transmitted by pulses of radio waves of two different lengths called "dots" and "dashes", which spell out text messages, usually in
501:
worked on adapting the newly discovered phenomenon of radio waves to communication, turning what was essentially a laboratory experiment up to that point into a useful communication system, building the first radiotelegraphy system using them. Preece and the
765:
range and can be heard in the receiver's earphones. During the "dots" and "dashes" of the signal, the beat tone is produced, while between them there is no carrier so no tone is produced. Thus the Morse code is audible as musical "beeps" in the earphones.
546:, which turned the transmitter on and off, producing short ("dot") and long ("dash") pulses of radio waves, groups of which comprised the letters and other symbols of the Morse code. At the receiver, the signals could be heard as musical "beeps" in the
777:. After this time BFOs were a standard part of radiotelegraphy receivers. Each time the radio was tuned to a different station frequency, the BFO frequency had to be changed also, so the BFO oscillator had to be tunable. In later
578:, meaning that the radio signal was not a single frequency but occupied a wide band of frequencies. Damped wave transmitters had a limited range and interfered with the transmissions of other transmitters on adjacent frequencies.
124:
Radiotelegraphy was used for long-distance person-to-person commercial, diplomatic, and military text communication throughout the first half of the 20th century. It became a strategically important capability during the two
471:, a device that would make a "click" sound when it received each pulse of current. The operator at the receiving station who knew Morse code would translate the clicking sounds to text and write down the message. The
2429:
Wireless
Telegraphy and High Frequency Electricity: A Manual Containing Detailed Information for the Construction of Transformers, Wireless Telegraph and High Frequency Apparatus, with Chapters on Their Theory and
805:
759:
276:
Radiotelegraphy is obsolete in commercial radio communication, and its last civilian use, requiring maritime shipping radio operators to use Morse code for emergency communications, ended in 1999 when the
792:
because they were cheap. CW became the standard method of transmitting radiotelegraphy by the 20s, damped wave spark transmitters were banned by 1930 and CW continues to be used today. Even today most
570:. As long as the telegraph key was pressed, the transmitter would produce a string of transient pulses of radio waves which repeated at an audio rate, usually between 50 and several thousand
951:
478:
By the 1860s, the telegraph was the standard way to send most urgent commercial, diplomatic and military messages, and industrial nations had built continent-wide telegraph networks, with
345:
2548:... The A B C of Wireless Telegraphy: A Plain Treatise on Hertzian Wave Signaling; Embracing Theory, Methods of Operation, and how to Build Various Pieces of the Apparatus Employed
2036:
939:
850:, using radio signals, which was developed in the 1930s and was for many years the only reliable form of communication between many distant countries. The most advanced standard,
1503:
550:
by the receiving operator, who would translate the code back into text. By 1910, communication by what had been called "Hertzian waves" was being universally referred to as "
661:
431:
Example of transatlantic radiotelegraph message recorded on paper tape at RCA's New York receiving center in 1920. The translation of the Morse code is given below the tape.
688:
574:. In a receiver's earphone, this sounded like a musical tone, rasp or buzz. Thus the Morse code "dots" and "dashes" sounded like beeps. Damped wave had a large frequency
2200:
864:
Today, due to more modern text transmission methods, Morse code radiotelegraphy for commercial use has become obsolete. On shipboard, the computer and satellite-linked
924:
617:
However, the radio receivers used for damped wave could not receive continuous wave. Because the CW signal produced while the key was pressed was just an unmodulated
348:
Class 1 licence in
Ireland, and Class 1 in Russia, both of which require proficiency in wireless telegraphy, offer additional privileges: a shorter and more desirable
101:
used radiotelegraphy. It continued to be the only type of radio transmission during the first few decades of radio, called the "wireless telegraphy era" up until
1228:
Individual nations enforce this prohibition in their communication laws. In the United States, this is the
Federal Communications Commission (FCC) regulations:
621:, it made no sound in a receiver's earphones. To receive a CW signal, some way had to be found to make the Morse code carrier wave pulses audible in a receiver.
510:
from 1896. Preece had become convinced of the idea through his experiments with wireless induction. However, the backing was withdrawn when
Marconi formed the
265:'s earphone or speaker as a sequence of buzzes or beeps, which is translated back to text by an operator who knows Morse code. With automatic radiotelegraphy
2977:
1350:
1296:
624:
This problem was solved by
Reginald Fessenden in 1901. In his "heterodyne" receiver, the incoming radiotelegraph signal is mixed in the receiver's
2457:
818:
911:, generally credited as first to develop practical radio-based wireless telegraphy communication, in 1901 with one of his first transmitters
3685:
3657:
3652:
2677:
1323:
293:, still exists in California, run primarily as a museum by volunteers, and occasional contacts with ships are made. In a minor legacy use,
1689:
1563:
323:, or just CW. A 2021 analysis of over 700 million communications logged by the Club Log blog, and a similar review of data logged by the
2033:
1925:
2201:
Title 47 –Telecommunication
Chapter I – Federal Communications Commission Subchapter A – General Part 13 – Commercial Radio Operators
282:
211:
and tended to interfere with other transmissions. This type of emission was banned by 1934, except for some legacy use on ships. The
1514:
340:
the
General class in Monaco, or Class 1 in Ukraine require Morse proficiency to access the full amateur radio spectrum including the
331:
communication, accounting for nearly 20% of contacts. This makes it more popular than voice communication, but not as popular as the
834:. Wireless telegraphy continued to be used for private person-to-person business, governmental, and military communication, such as
701:
2363:
Wireless Telegraphy and Wireless Telephony: An Understandable Presentation of the Science of Wireless Transmission of Intelligence
2147:
289:
operators, and military services require signalmen to be trained in Morse code for emergency communication. A CW coastal station,
129:
since a nation without long-distance radiotelegraph stations could be isolated from the rest of the world by an enemy cutting its
86:
the pulses are audible in the receiver's speaker as beeps, which are translated back to text by an operator who knows Morse code.
3767:
809:
In World War I balloons were used as a quick way to raise wire antennas for military field radiotelegraph stations. Balloons at
1377:
1123:
Bondyopadhyay, Prebir K. (1995). "Guglielmo Marconi – The father of long distance radio communication – An engineer's tribute".
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511:
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1969:
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1033:
Hawkins' Electrical Dictionary: A cyclopedia of words, terms, phrases and data used in the electric arts, trades and sciences
880:
822:
586:
184:
788:
Continuous-wave vacuum tube transmitters replaced the other types of transmitter with the availability of power tubes after
3757:
2148:"Requirements for Telex and Gentex operation to be met by synchronous multiplex equipment described in recommendation R.44"
1107:
2811:
137:. It is also taught by the military for use in emergency communications. However, commercial radiotelegraphy is obsolete.
117:) to be transmitted by radio. Beginning about 1908, powerful transoceanic radiotelegraphy stations transmitted commercial
3736:
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3515:
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278:
581:
After 1905 new types of radiotelegraph transmitters were invented which transmitted code using a new modulation method:
238:
networks (RTTY). Morse code radiotelegraphy was gradually replaced by radioteletype in most high volume applications by
3441:
17:
3535:
1699:
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1306:
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35:
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The BFO was rare until the invention in 1913 of the first practical electronic oscillator, the vacuum tube feedback
3320:
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2670:
409:
Typical commercial radiotelegraphy receiver from the first decade of the 20th century. The "dots" and "dashes" of
467:
to the telegraph line, sending current down the wire. At the receiving office, the current pulses would operate a
3431:
1588:"History of the Atlantic Cable & Submarine Telegraphy - Frank Leslie's Illustrated Newspaper 1858 Cable News"
475:
was used as the return path for current in the telegraph circuit, to avoid having to use a second overhead wire.
1489:
3426:
2440:
Poincaré, Lucien (28 February 2005) . "Chapter VII: A Chapter in the History of Science: Wireless telegraphy".
2247:
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1262:
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208:
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2604:
A History of Wireless Telegraphy, 1838–1899: including some bare-wire proposals for subaqueous telegraphs
2561:
A History of Wireless Telegraphy, 1838-1899: Including Some Bare-wire Proposals for Subaqueous Telegraphs
554:", and the term wireless telegraphy has been largely replaced by the more modern term "radiotelegraphy".
324:
2294:
2215:
Sarkar, T. K.; Mailloux, Robert; Oliner, Arthur A.; Salazar-Palma, M.; Sengupta, Dipak L. (2006-01-30).
2183:
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earlyradiohistory.us, United States Early Radio History, Thomas H. White, section 22, Word Origins-Radio
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1398:
1279:
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as emission type A1A). As long as the telegraph key was pressed, the transmitter produced a continuous
226:(CW), which is still used today. To receive CW transmissions, the receiver requires a circuit called a
3347:
3308:
3153:
3053:
2982:
2915:
2742:
1665:
Ingenious Ireland: A County-by-County Exploration of the Mysteries and Marvels of the Ingenious Irish
839:
761:. If the BFO frequency is near enough to the radio station's frequency, the beat frequency is in the
633:
506:(GPO) in Britain at first supported and gave financial backing to Marconi's experiments conducted on
479:
294:
227:
130:
1612:
639:
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in 1887, and the development of practical radiotelegraphy transmitters and receivers by about 1899.
156:
Illustration from 1912 of a radiotelegraph operator on a ship sending an emergency SOS call for help
3706:
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188:
1985:
1900:
1422:
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2712:
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1950:
1055:
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603:
336:
785:(IF) produced by the superheterodyne's detector. Therefore, the BFO could be a fixed frequency.
3467:
3253:
3068:
3013:
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2821:
2786:
2260:
1663:
782:
298:
231:
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1882:
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1636:
1207:
1006:
830:) began to displace radiotelegraphy by the 1920s for many applications, making possible radio
215:(valve) transmitters which came into use after 1920 transmitted code by pulses of unmodulated
3369:
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3058:
3038:
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1933:
1800:
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Efforts to find a way to transmit telegraph signals without wires grew out of the success of
200:
58:
2702:
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networks, the first instant telecommunication systems. Developed beginning in the 1830s, a
3283:
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2614:
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2010:
1929:
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503:
290:
192:
2335:
2078:"Broadcasting | Definition, History, Types, Systems, Examples, & Facts | Britannica"
1442:
1083:
945:
German officers and troops manning a wireless field telegraph station during World War I
3520:
3477:
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3278:
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3183:
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614:. These slowly replaced the spark transmitters in high power radiotelegraphy stations.
611:
607:
436:
361:
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ships for both commercial purposes and passenger messages. The transmission of sound (
89:
Radiotelegraphy was the first means of radio communication. The first practical radio
3560:
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2222:
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1965:
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1329:
1302:
1231:"Section 2.201: Emission, modulation, and transmission characteristics, footnote (f)"
1059:
908:
810:
531:
498:
468:
98:
3228:
1085:
American Telegraphy and Encyclopedia of the Telegraph: Systems, Apparatus, Operation
403:
257:
of different lengths called "dots" and "dashes", which encode characters of text in
3565:
3525:
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3401:
3359:
3273:
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2401:
2272:
2242:. Science, culture and society. New York London Sydney Toronto: J. Wiley and sons.
1140:
1128:
625:
599:
482:
allowing telegraph messages to bridge oceans. However installing and maintaining a
444:
305:
62:
514:. GPO lawyers determined that the system was a telegraph under the meaning of the
3193:
3048:
2816:
2791:
2779:
2586:
2546:
2473:. University of California. London, New York and Bombay, Longmans, Green, and Co.
2427:
2374:
2361:
2322:
2216:
2040:
1235:
Code of Federal Regulations, Title 47, Chapter I, Subchapter A, Part 2, Subpart C
1155:
1010:
876:
778:
774:
762:
582:
507:
414:
382:
320:
223:
176:
1986:"Superheterodyne reception | Radio waves, Frequency, Amplification | Britannica"
253:, which turns the radio transmitter on and off, producing pulses of unmodulated
3391:
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110:
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83:
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1691:
Icons of the invention: the makers of the modern world from Gutenberg to Gates
270:
162:
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3540:
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3303:
3218:
3108:
3103:
3093:
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1298:
Electrical, Electronics and Computer Engineering for Scientists and Engineers
1132:
988:
843:
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543:
515:
456:
328:
301:
286:
250:
235:
180:
134:
75:
1857:
3418:
3258:
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3133:
3098:
3033:
2932:
2922:
2774:
831:
817:
The International Radiotelegraph Union was unofficially established at the
618:
539:
352:
in both countries, and the right to use a higher transmit power in Russia.
254:
239:
219:
114:
2053:
1763:
1730:
1638:
Icons of Invention: The Makers of the Modern World from Gutenberg to Gates
3618:
3268:
3178:
3163:
3123:
3083:
2942:
931:
847:
789:
567:
266:
212:
204:
102:
90:
79:
2535:
Wireless Telegraphy: Its Origins, Development, Inventions, and Apparatus
2419:. University of Wisconsin - Madison. New York, D. Van Nostrand company;
2340:. University of California Libraries. New York, D. Van Nostrand company.
1743:
781:
receivers from the 1930s on, the BFO signal was mixed with the constant
375:
3623:
3330:
3028:
2937:
2893:
2863:
2841:
2486:. University of Michigan. London ; New York : Cassell and Co.
858:
695:
527:
491:
460:
410:
258:
216:
196:
71:
54:
39:
1887:
Transactions of the International Electrical Congress, St. Louis, 1904
3608:
3073:
2888:
2655:
2337:
Radiodynamics, the wireless control of torpedoes and other mechanisms
2015:
Circuit Board Fabrication and PCB Assembly Turnkey Services - WellPCB
1539:"1830s – 1860s: Telegraph | Imagining the Internet | Elon University"
1409:
590:
547:
459:, creating pulses of electric current which spelled out a message in
394:
349:
327:, both show that wireless telegraphy is the 2nd most popular mode of
309:
126:
74:. In a manual system, the sending operator taps on a switch called a
3603:
3593:
3510:
3335:
3158:
2261:"A technological survey of broadcasting's "pre-history," 1876–1920"
835:
118:
1744:"Marconi at Mizen Head Visitor Centre Ireland Visitor Attractions"
443:
was a person-to-person text message system consisting of multiple
3598:
3583:
2801:
2633:
2214:
930:
German troops erecting a wireless field telegraph station during
846:
networks. The ultimate implementation of wireless telegraphy was
628:
crystal or vacuum tube with a constant sine wave generated by an
2591:. American Institute of Electrical Engineers. 1919. p. 306.
1443:"ARRL Letter, FT8 Accounts for Nearly Two-Thirds of HF Activity"
868:
system have largely replaced Morse as a means of communication.
797:
produced for use in shortwave communication stations have BFOs.
3628:
3588:
2910:
1180:"Zimmermann Telegram | Facts, Text, & Outcome | Britannica"
1112:. Washington D.C.: U.S. Bureau of the Census. pp. 118–119.
452:
246:
121:
traffic between countries at rates up to 200 words per minute.
2588:
Transactions of the American Institute of Electrical Engineers
2525:. University of Michigan. New York, McGraw publishing company.
2373:
Massie, Walter Wentworth; Underhill, Charles Reginald (1908).
1011:
Transactions of the American Institute of Electrical Engineers
754:{\displaystyle f_{\text{BEAT}}=|f_{\text{IN}}-f_{\text{BFO}}|}
451:. To send a message, an operator at one office would tap on a
3613:
3550:
2858:
2499:. University of Michigan. New York, D. Van Nostrand company;
1378:"Why the Navy Sees Morse Code as the Future of Communication"
865:
851:
698:) at the difference between the two frequencies is produced:
571:
551:
490:
The successful solution to this problem was the discovery of
245:
In manual radiotelegraphy the sending operator manipulates a
1281:
The History of Communications - Electronics in the U.S. Navy
175:
Wireless telegraphy or radiotelegraphy, commonly called CW (
3555:
1926:"Carrier wave with no modulation transports no information"
1007:
Wireless Telephony – By R. A. Fessenden (Illustrated.)
1264:
Contact at Sea: A History of Maritime Radio Communications
566:
used until 1920 transmitted by a modulation method called
542:). Instead, the operator would send the text message on a
497:
Over several years starting in 1894, the Italian inventor
261:. At the receiving location, Morse code is audible in the
2360:
Ashley, Charles Grinnell; Hayward, Charles Brian (1912).
1237:. US Government Publishing Office website. 1 October 2007
332:
150:
30:
1964:. The Antique Wireless Association, Inc.: 287–289 2009.
1156:"Technology You Didn't Know Still Existed: The Telegram"
522:
With this development, wireless telegraphy came to mean
82:
on and off, producing the pulses of radio waves. At the
2011:"Beat Frequency Oscillator- Principle and Applications"
1883:"System for producing continuous electric oscillations"
1423:"Club Log activity report – 2021 update | G7VJR's Blog"
1013:. New York: American Institute of Electrical Engineers.
690:. In the detector the two frequencies subtract, and a
598:(Poulsen arc) transmitter, invented by Danish engineer
1294:
179:), ICW (interrupted continuous wave) transmission, or
2522:
Wireless telegraphy; its history, theory and practice
2376:
Wireless Telegraphy and Telephony Popularly Explained
1723:
The Electric Telegraph: A Social and Economic History
1473:"CEPT Radio Amateur Licence Recommendation T/R 61-01"
1005:
American Institute of Electrical Engineers. (1908). "
857:, automated both routing and encoding of messages by
704:
669:
642:
168:
Modern amateur radio operator transmitting Morse code
2531:
2353:. University of Michigan. New York : Macmillan.
2311:
The Encyclopædia Britannica: Submarine Mines-Tom-tom
1504:"Условия использования выделенных полос радиочастот"
1889:. Vol. 2. J.B. Lyon Company. pp. 963–971.
1617:
American Association for the Advancement of Science
975:
originally American Telephone and Telegraph Company
891:licenses earned under the old 20 wpm requirement.)
2480:Simmons, Harold H. (1909). "Wireless telegraphy".
2347:Thompson, Silvanus P. (Silvanus Phillips) (1915).
2034:ICAO and the International Telecommunication Union
1047:
753:
682:
655:
538:used until World War I, could not transmit voice (
2572:"Telegraphing across space, Electric wave method"
2557:
2519:Collins, A. Frederick (Archie Frederick) (1905).
2505:
663:is offset from the radio transmitter's frequency
308:service still transmit their one to three letter
3749:
1901:"Milestones:Alexanderson Radio Alternator, 1904"
1799:Siwiak, Kazimierz; McKeown, Debra (2004-06-07).
1050:Merriam-Webster's Collegiate Dictionary: 11th Ed
195:method. It was transmitted by several different
2538:. University of California. D. Van Nostrand Co.
2372:
2350:Elementary lessons in electricity and magnetism
1661:
1295:Krishnamurthy, K. A.; Raghuveer, M. R. (2007).
1109:Special Reports: Telephones and Telegraphs 1902
463:. When the key was pressed, it would connect a
2564:. University of Michigan. Dodd, Mead & co.
1613:"Heinrich Hertz and electromagnetic radiation"
961:, using a hydrogen balloon to lift the antenna
2671:
2512:. University of Michigan. Whittaker & Co.
2359:
1798:
1288:
1122:
819:first International Radiotelegraph Convention
2393:. Simmons-Boardman Publishing Company. 1911.
2054:"13. Radio During World War One (1914-1919)"
1256:
1254:
1252:
3686:Global telecommunications regulation bodies
1348:
1106:Steuart, William Mott; et al. (1906).
3722:
2678:
2664:
2470:The principles of electric wave telegraphy
2456:: CS1 maint: location missing publisher (
1562:Laboratory, National High Magnetic Field.
199:methods during its history. The primitive
2258:
2124:"BT Museum Memorial Pages - Telegraphy 2"
1564:"Morse Telegraph – 1844 - Magnet Academy"
1355:. Technical Publications. p. 12.55.
1260:
1249:
1088:. New York: Maver Publishing Co. p.
879:(CW) radiotelegraphy is regulated by the
335:digital mode, which accounted for 60% of
2439:
2346:
2333:
2307:
1629:
1513:(in Russian). 2015-10-16. Archived from
1125:25th European Microwave Conference, 1995
804:
636:(BFO). The frequency of the oscillator
447:linked by an overhead wire supported on
426:
413:were recorded in ink on paper tape by a
319:world-wide, who commonly refer to it as
53:is the transmission of text messages by
29:
2544:
2518:
2479:
2466:
2425:
2406:. London, New York, Whittaker & co.
2399:
2320:
2240:Syntony and spark: the origins of radio
1880:
1610:
1271:
1202:
1200:
1153:
1105:
1040:
1029:
994:
512:Wireless Telegraph & Signal Company
14:
3750:
2685:
2492:
2412:
2403:Wireless telegraphy and Hertzian waves
2259:Sivowitch, Elliot N. (December 1970).
2237:
2103:"Typing in Airplane Received by Radio"
1561:
1349:Godse, Atul P.; Bakshi, U. A. (2009).
1325:Basic Radio: Principles and Technology
1301:. New Age International. p. 375.
1277:
1099:
1023:
530:transmitted by radio waves. The first
381:British Post Office engineers inspect
271:International Telegraph Alphabet No. 2
230:(BFO). The third type of modulation,
2659:
2387:"Developments in wireless telegraphy"
2152:International Telecommunication Union
1945:
1943:
1851:
1849:
1824:
1822:
1715:
1467:
1465:
1463:
1420:
1375:
1369:
1342:
1321:
1315:
1081:
1036:. Theodore Audel and Co. p. 498.
881:International Telecommunication Union
823:International Telecommunication Union
587:International Telecommunication Union
285:system. However it is still used by
185:International Telecommunication Union
133:. Radiotelegraphy remains popular in
3732:
2366:. American School of Correspondence.
2334:Miessner, Benjamin Franklin (1916).
1490:"Amateur Station Licence Guidelines"
1399:Morse code training in the Air Force
1197:
1075:
1054:. Merriam-Webster Co. 2004. p.
269:at both ends use a code such as the
2188:International Maritime Organization
2170:International Maritime Organization
1668:. Simon and Schuster. p. 313.
315:Radiotelegraphy is popular amongst
279:International Maritime Organization
24:
2496:A handbook of wireless telegraphy;
2483:Outlines of electrical engineering
2416:A handbook of wireless telegraphy;
2299:The New International Encyclopædia
2208:
2008:
1940:
1846:
1819:
1460:
1267:. The Gregg Press. pp. 26–30.
1222:
25:
3779:
2596:
2509:Wireless Telegraphy and Telephony
2443:The New Physics and Its Evolution
1611:Edwards, Steven A. (2012-10-12).
888:Federal Communications Commission
821:in 1906, and was merged into the
3731:
3721:
3712:
3711:
3700:
3321:Free-space optical communication
2627:The Story of Wireless Telegraphy
2426:Twining, Harry La Verne (1909).
2391:International Marine Engineering
2324:Textebook on wireless telegraphy
2301:. Dodd, Mead. 1922. p. 637.
1421:Wells, Michael (27 March 2021).
950:
938:
923:
901:
402:
374:
281:switched to the satellite-based
161:
149:
2194:
2176:
2158:
2140:
2116:
2095:
2070:
2046:
2027:
2002:
1978:
1918:
1893:
1874:
1802:Ultra-wideband Radio Technology
1792:
1768:
1757:
1736:
1682:
1655:
1641:. ABC-CLIO. 2009. p. 162.
1604:
1580:
1555:
1531:
1496:
1482:
1435:
1414:
1403:
1392:
295:VHF omnidirectional range (VOR)
42:transmitting by radiotelegraphy
3768:Wireless communication systems
2493:Murray, James Erskine (1907).
2467:Fleming, John Ambrose (1908).
2413:Murray, James Erskine (1907).
2400:Bottone, Selimo Romeo (1910).
1855:
1511:General Radio Frequency Centre
1492:. 2018-04-16. pp. 17, 32.
1208:"Maritime Morse Is Tapped Out"
1172:
1147:
1116:
747:
719:
656:{\displaystyle f_{\text{BFO}}}
65:. Before about 1910, the term
13:
1:
2649:Principles of Radiotelegraphy
2641:Principles of Radiotelegraphy
2532:Charles Henry Sewall (1903).
871:
683:{\displaystyle f_{\text{IN}}}
140:
3707:Telecommunication portal
3488:Telecommunications equipment
2578:. Biggs & Company. 1898.
2551:. Bubier publishing Company.
1376:Maxey, Kyle (17 July 2017).
1261:Schroeder, Peter B. (1967).
1210:. Wired website. 6 July 1998
1154:Spencer, Luke (2015-06-02).
1017:
883:(ITU) as emission type A1A.
366:History of telecommunication
203:used until 1920 transmitted
7:
3758:History of radio technology
3224:Alexander Stepanovich Popov
2634:Sparks Telegraph Key Review
2238:Aitken, Hugo G. J. (1976).
1905:IEEE Global History Network
1082:Maver, William Jr. (1903).
966:
800:
325:American Radio Relay League
10:
3784:
2928:Telecommunications history
2558:John Joseph Fahie (1900).
2506:Domenico Mazzotto (1906).
2379:. D. Van Nostrand Company.
2314:. At the University Press.
1881:Poulsen, Valdemar (1905).
1858:"Emissions Designator A1A"
1776:"Spark Transmitter Basics"
1725:, David and Charles, 1973
1380:. Engineering. com website
1030:Hawkins, Nehemiah (1910).
999:
894:
557:
480:submarine telegraph cables
359:
355:
131:submarine telegraph cables
105:, when the development of
38:radio operator in 1943 in
3695:
3637:
3574:
3536:Public Switched Telephone
3496:
3460:
3417:
3358:
3348:telecommunication circuit
3309:Fiber-optic communication
3292:
3054:Francis Blake (telephone)
3001:
2849:Optical telecommunication
2693:
2277:10.1080/08838157009363620
1284:. U.S. Navy. p. 509.
840:diplomatic communications
634:beat frequency oscillator
632:in the receiver called a
606:, invented 1906–1912 by
273:and produced typed text.
234:(FSK) was used mainly by
228:beat frequency oscillator
97:invented in 1894–1895 by
3447:Orbital angular-momentum
2884:Satellite communications
2723:Communications satellite
2545:Trevert, Edward (1904).
2321:Stanley, Rupert (1919).
1805:. Wiley. pp. 1–20.
1662:Mulvihill, Mary (2003).
1133:10.1109/EUMA.1995.337090
959:German South West Africa
957:Mobile radio station in
795:communications receivers
585:(CW) (designated by the
189:emission type A1A or A2A
183:, and designated by the
3326:Molecular communication
3149:Gardiner Greene Hubbard
2978:Undersea telegraph line
2713:Cable protection system
2576:The Electrical Engineer
2308:Chisholm, Hugh (1911).
2265:Journal of Broadcasting
2043:– ICAO official website
2009:Lu, Emma (2022-02-25).
1328:. Newnes. p. 134.
984:Imperial Wireless Chain
604:Alexanderson alternator
27:Method of communication
3468:Communication protocol
3254:Charles Sumner Tainter
3069:Walter Houser Brattain
3014:Edwin Howard Armstrong
2822:Information revolution
2184:"Introduction/History"
1278:Howeth, L. S. (1963).
814:
783:intermediate frequency
755:
684:
657:
564:spark-gap transmitters
536:spark gap transmitters
432:
337:amateur radio contacts
232:frequency-shift keying
207:, which had very wide
201:spark-gap transmitters
43:
3442:Polarization-division
3174:Narinder Singh Kapany
3139:Erna Schneider Hoover
3059:Jagadish Chandra Bose
3039:Alexander Graham Bell
2770:online video platform
2615:1901 (second edition)
2295:"Wireless telegraphy"
2166:"Radiocommunications"
1951:"Heterodyne receiver"
1834:TheFreeDictionary.com
808:
756:
685:
658:
630:electronic oscillator
430:
360:Further information:
344:(HF) bands. Further,
59:electrical telegraphy
33:
3284:Vladimir K. Zworykin
3244:Almon Brown Strowger
3214:Charles Grafton Page
2869:Prepaid mobile phone
2797:Electrical telegraph
2610:1899 (first edition)
2058:earlyradiohistory.us
1094:wireless telegraphy.
1070:wireless telegraphy.
995:References and notes
979:Electrical telegraph
973:AT&T Corporation
702:
667:
640:
107:amplitude modulation
3234:Johann Philipp Reis
2993:Wireless revolution
2955:The Telephone Cases
2812:Hydraulic telegraph
2622:Alfred Thomas Story
2602:John Joseph Fahie,
2585:"Radio telephony".
2218:History of Wireless
2128:www.samhallas.co.uk
1930:University of Texas
1721:Kieve, Jeffrey L.,
1322:Poole, Ian (1998).
842:, and evolved into
504:General Post Office
193:radio communication
67:wireless telegraphy
47:Wireless telegraphy
3432:Frequency-division
3409:Telephone exchange
3279:Charles Wheatstone
3209:Jun-ichi Nishizawa
3184:Innocenzo Manzetti
3119:Reginald Fessenden
2854:Optical telegraphy
2687:Telecommunications
2327:. Longmans, Green.
2110:The New York Times
2082:www.britannica.com
2039:2018-11-06 at the
1990:www.britannica.com
1694:. ABC-CLIO. 2009.
1592:atlantic-cable.com
1568:nationalmaglab.org
1184:www.britannica.com
815:
751:
680:
653:
612:Ernst Alexanderson
608:Reginald Fessenden
532:radio transmitters
437:electric telegraph
433:
362:Invention of radio
44:
18:Wireless telegraph
3745:
3744:
3483:Store and forward
3478:Data transmission
3392:Network switching
3343:Transmission line
3189:Guglielmo Marconi
3154:Internet pioneers
3019:Mohamed M. Atalla
2988:Whistled language
2638:Cyril M. Jansky,
2228:978-0-471-78301-5
1971:978-0-9741994-1-2
1830:"continuous wave"
1812:978-0-470-85931-5
1675:978-0-684-02094-5
1648:978-0-313-34743-6
1410:Coast Station KSM
1352:Basic Electronics
909:Guglielmo Marconi
811:Tempelhofer Field
743:
730:
712:
677:
650:
602:in 1903, and the
499:Guglielmo Marconi
469:telegraph sounder
445:telegraph offices
99:Guglielmo Marconi
16:(Redirected from
3775:
3735:
3734:
3725:
3724:
3715:
3714:
3705:
3704:
3703:
3576:Notable networks
3566:Wireless network
3506:Cellular network
3498:Types of network
3473:Computer network
3360:Network topology
3274:Thomas A. Watson
3129:Oliver Heaviside
3114:Philo Farnsworth
3089:Daniel Davis Jr.
3064:Charles Bourseul
3024:John Logie Baird
2733:Data compression
2728:Computer network
2680:
2673:
2666:
2657:
2656:
2592:
2579:
2565:
2552:
2539:
2526:
2513:
2500:
2487:
2474:
2461:
2455:
2447:
2434:
2420:
2407:
2394:
2380:
2367:
2354:
2341:
2328:
2315:
2302:
2288:
2253:
2232:
2203:
2198:
2192:
2191:
2180:
2174:
2173:
2162:
2156:
2155:
2144:
2138:
2137:
2135:
2134:
2120:
2114:
2113:
2107:
2099:
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2090:
2089:
2074:
2068:
2067:
2065:
2064:
2050:
2044:
2031:
2025:
2024:
2022:
2021:
2006:
2000:
1999:
1997:
1996:
1982:
1976:
1975:
1955:
1947:
1938:
1937:
1932:. Archived from
1922:
1916:
1915:
1913:
1912:
1897:
1891:
1890:
1878:
1872:
1871:
1869:
1868:
1853:
1844:
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1841:
1840:
1826:
1817:
1816:
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1786:
1772:
1766:
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1755:
1754:
1752:
1751:
1740:
1734:
1719:
1713:
1712:
1710:
1708:
1686:
1680:
1679:
1659:
1653:
1652:
1633:
1627:
1626:
1624:
1623:
1608:
1602:
1601:
1599:
1598:
1584:
1578:
1577:
1575:
1574:
1559:
1553:
1552:
1550:
1549:
1535:
1529:
1528:
1526:
1525:
1519:
1508:
1500:
1494:
1493:
1486:
1480:
1479:
1477:
1469:
1458:
1457:
1455:
1454:
1439:
1433:
1432:
1430:
1429:
1418:
1412:
1407:
1401:
1396:
1390:
1389:
1387:
1385:
1373:
1367:
1366:
1346:
1340:
1339:
1319:
1313:
1312:
1292:
1286:
1285:
1275:
1269:
1268:
1258:
1247:
1246:
1244:
1242:
1226:
1220:
1219:
1217:
1215:
1204:
1195:
1194:
1192:
1191:
1176:
1170:
1169:
1167:
1166:
1151:
1145:
1144:
1120:
1114:
1113:
1103:
1097:
1096:
1079:
1073:
1072:
1053:
1044:
1038:
1037:
1027:
954:
942:
927:
905:
813:, Germany, 1908.
760:
758:
757:
752:
750:
745:
744:
741:
732:
731:
728:
722:
714:
713:
710:
689:
687:
686:
681:
679:
678:
675:
662:
660:
659:
654:
652:
651:
648:
600:Valdemar Poulsen
406:
378:
306:radio navigation
304:in the aviation
165:
153:
78:which turns the
21:
3783:
3782:
3778:
3777:
3776:
3774:
3773:
3772:
3748:
3747:
3746:
3741:
3701:
3699:
3691:
3633:
3570:
3492:
3456:
3413:
3362:
3354:
3295:
3288:
3194:Robert Metcalfe
3049:Tim Berners-Lee
2997:
2817:Information Age
2689:
2684:
2599:
2584:
2570:
2449:
2448:
2385:
2293:
2250:
2229:
2211:
2209:Further reading
2206:
2199:
2195:
2182:
2181:
2177:
2164:
2163:
2159:
2146:
2145:
2141:
2132:
2130:
2122:
2121:
2117:
2105:
2101:
2100:
2096:
2087:
2085:
2076:
2075:
2071:
2062:
2060:
2052:
2051:
2047:
2041:Wayback Machine
2032:
2028:
2019:
2017:
2007:
2003:
1994:
1992:
1984:
1983:
1979:
1972:
1953:
1949:
1948:
1941:
1924:
1923:
1919:
1910:
1908:
1899:
1898:
1894:
1879:
1875:
1866:
1864:
1854:
1847:
1838:
1836:
1828:
1827:
1820:
1813:
1797:
1793:
1784:
1782:
1780:home.freeuk.net
1774:
1773:
1769:
1762:
1758:
1749:
1747:
1746:. Mizenhead.net
1742:
1741:
1737:
1720:
1716:
1706:
1704:
1702:
1688:
1687:
1683:
1676:
1660:
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1609:
1605:
1596:
1594:
1586:
1585:
1581:
1572:
1570:
1560:
1556:
1547:
1545:
1537:
1536:
1532:
1523:
1521:
1517:
1506:
1502:
1501:
1497:
1488:
1487:
1483:
1475:
1471:
1470:
1461:
1452:
1450:
1441:
1440:
1436:
1427:
1425:
1419:
1415:
1408:
1404:
1397:
1393:
1383:
1381:
1374:
1370:
1363:
1347:
1343:
1336:
1320:
1316:
1309:
1293:
1289:
1276:
1272:
1259:
1250:
1240:
1238:
1229:
1227:
1223:
1213:
1211:
1206:
1205:
1198:
1189:
1187:
1178:
1177:
1173:
1164:
1162:
1152:
1148:
1127:. p. 879.
1121:
1117:
1104:
1100:
1080:
1076:
1066:
1046:
1045:
1041:
1028:
1024:
1020:
1002:
997:
969:
962:
955:
946:
943:
934:
928:
919:
906:
897:
877:Continuous wave
874:
861:transmissions.
803:
779:superheterodyne
775:Edwin Armstrong
763:audio frequency
746:
740:
736:
727:
723:
718:
709:
705:
703:
700:
699:
674:
670:
668:
665:
664:
647:
643:
641:
638:
637:
591:sinusoidal wave
583:continuous wave
560:
524:radiotelegraphy
508:Salisbury Plain
449:telegraph poles
425:
424:
423:
422:
421:
415:siphon recorder
407:
399:
398:
385:'s transmitter
379:
368:
358:
321:continuous wave
312:in Morse code.
224:continuous wave
177:continuous wave
173:
172:
171:
170:
169:
166:
158:
157:
154:
143:
113:allowed sound (
57:, analogous to
51:radiotelegraphy
28:
23:
22:
15:
12:
11:
5:
3781:
3771:
3770:
3765:
3760:
3743:
3742:
3740:
3739:
3729:
3719:
3709:
3696:
3693:
3692:
3690:
3689:
3682:
3677:
3672:
3667:
3662:
3661:
3660:
3655:
3647:
3641:
3639:
3635:
3634:
3632:
3631:
3626:
3621:
3616:
3611:
3606:
3601:
3596:
3591:
3586:
3580:
3578:
3572:
3571:
3569:
3568:
3563:
3558:
3553:
3548:
3543:
3538:
3533:
3528:
3523:
3518:
3513:
3508:
3502:
3500:
3494:
3493:
3491:
3490:
3485:
3480:
3475:
3470:
3464:
3462:
3458:
3457:
3455:
3454:
3449:
3444:
3439:
3434:
3429:
3427:Space-division
3423:
3421:
3415:
3414:
3412:
3411:
3406:
3405:
3404:
3399:
3389:
3388:
3387:
3377:
3372:
3366:
3364:
3356:
3355:
3353:
3352:
3351:
3350:
3340:
3339:
3338:
3328:
3323:
3318:
3317:
3316:
3306:
3300:
3298:
3290:
3289:
3287:
3286:
3281:
3276:
3271:
3266:
3264:Camille Tissot
3261:
3256:
3251:
3246:
3241:
3239:Claude Shannon
3236:
3231:
3229:Tivadar Puskás
3226:
3221:
3216:
3211:
3206:
3201:
3199:Antonio Meucci
3196:
3191:
3186:
3181:
3176:
3171:
3169:Charles K. Kao
3166:
3161:
3156:
3151:
3146:
3144:Harold Hopkins
3141:
3136:
3131:
3126:
3121:
3116:
3111:
3106:
3101:
3096:
3091:
3086:
3081:
3076:
3071:
3066:
3061:
3056:
3051:
3046:
3044:Emile Berliner
3041:
3036:
3031:
3026:
3021:
3016:
3011:
3005:
3003:
2999:
2998:
2996:
2995:
2990:
2985:
2983:Videotelephony
2980:
2975:
2974:
2973:
2968:
2958:
2951:
2946:
2940:
2935:
2930:
2925:
2920:
2919:
2918:
2913:
2908:
2898:
2897:
2896:
2886:
2881:
2879:Radiotelephone
2876:
2871:
2866:
2861:
2856:
2851:
2846:
2845:
2844:
2834:
2829:
2824:
2819:
2814:
2809:
2804:
2799:
2794:
2789:
2784:
2783:
2782:
2777:
2772:
2767:
2765:Internet video
2757:
2756:
2755:
2750:
2745:
2740:
2730:
2725:
2720:
2715:
2710:
2705:
2699:
2697:
2691:
2690:
2683:
2682:
2675:
2668:
2660:
2654:
2653:
2645:
2636:
2631:
2619:
2618:
2617:
2612:
2598:
2597:External links
2595:
2594:
2593:
2581:
2580:
2567:
2566:
2554:
2553:
2541:
2540:
2528:
2527:
2515:
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2408:
2396:
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2368:
2356:
2355:
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2330:
2329:
2317:
2316:
2304:
2303:
2290:
2289:
2255:
2254:
2248:
2234:
2233:
2227:
2210:
2207:
2205:
2204:
2193:
2175:
2157:
2139:
2115:
2094:
2069:
2045:
2026:
2001:
1977:
1970:
1958:The AWA Review
1939:
1936:on 2008-04-14.
1917:
1892:
1873:
1845:
1818:
1811:
1791:
1767:
1756:
1735:
1714:
1700:
1681:
1674:
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1628:
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1579:
1554:
1530:
1495:
1481:
1459:
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1413:
1402:
1391:
1368:
1361:
1341:
1334:
1314:
1307:
1287:
1270:
1248:
1221:
1196:
1171:
1146:
1115:
1098:
1074:
1064:
1039:
1021:
1019:
1016:
1015:
1014:
1001:
998:
996:
993:
992:
991:
986:
981:
976:
968:
965:
964:
963:
956:
949:
947:
944:
937:
935:
929:
922:
920:
915:and receivers
907:
900:
896:
893:
873:
870:
828:radiotelephony
802:
799:
749:
739:
735:
726:
721:
717:
708:
692:beat frequency
673:
646:
562:The primitive
559:
556:
484:telegraph line
441:telegraph line
408:
401:
400:
380:
373:
372:
371:
370:
369:
357:
354:
342:high frequency
317:radio amateurs
167:
160:
159:
155:
148:
147:
146:
145:
144:
142:
139:
111:radiotelephony
26:
9:
6:
4:
3:
2:
3780:
3769:
3766:
3764:
3761:
3759:
3756:
3755:
3753:
3738:
3730:
3728:
3720:
3718:
3710:
3708:
3698:
3697:
3694:
3687:
3683:
3681:
3678:
3676:
3673:
3671:
3668:
3666:
3663:
3659:
3656:
3654:
3651:
3650:
3648:
3646:
3643:
3642:
3640:
3636:
3630:
3627:
3625:
3622:
3620:
3617:
3615:
3612:
3610:
3607:
3605:
3602:
3600:
3597:
3595:
3592:
3590:
3587:
3585:
3582:
3581:
3579:
3577:
3573:
3567:
3564:
3562:
3559:
3557:
3554:
3552:
3549:
3547:
3544:
3542:
3539:
3537:
3534:
3532:
3529:
3527:
3524:
3522:
3519:
3517:
3514:
3512:
3509:
3507:
3504:
3503:
3501:
3499:
3495:
3489:
3486:
3484:
3481:
3479:
3476:
3474:
3471:
3469:
3466:
3465:
3463:
3459:
3453:
3452:Code-division
3450:
3448:
3445:
3443:
3440:
3438:
3437:Time-division
3435:
3433:
3430:
3428:
3425:
3424:
3422:
3420:
3416:
3410:
3407:
3403:
3400:
3398:
3395:
3394:
3393:
3390:
3386:
3383:
3382:
3381:
3378:
3376:
3373:
3371:
3368:
3367:
3365:
3363:and switching
3361:
3357:
3349:
3346:
3345:
3344:
3341:
3337:
3334:
3333:
3332:
3329:
3327:
3324:
3322:
3319:
3315:
3314:optical fiber
3312:
3311:
3310:
3307:
3305:
3304:Coaxial cable
3302:
3301:
3299:
3297:
3291:
3285:
3282:
3280:
3277:
3275:
3272:
3270:
3267:
3265:
3262:
3260:
3257:
3255:
3252:
3250:
3247:
3245:
3242:
3240:
3237:
3235:
3232:
3230:
3227:
3225:
3222:
3220:
3219:Radia Perlman
3217:
3215:
3212:
3210:
3207:
3205:
3202:
3200:
3197:
3195:
3192:
3190:
3187:
3185:
3182:
3180:
3177:
3175:
3172:
3170:
3167:
3165:
3162:
3160:
3157:
3155:
3152:
3150:
3147:
3145:
3142:
3140:
3137:
3135:
3132:
3130:
3127:
3125:
3122:
3120:
3117:
3115:
3112:
3110:
3109:Lee de Forest
3107:
3105:
3104:Thomas Edison
3102:
3100:
3097:
3095:
3094:Donald Davies
3092:
3090:
3087:
3085:
3082:
3080:
3079:Claude Chappe
3077:
3075:
3072:
3070:
3067:
3065:
3062:
3060:
3057:
3055:
3052:
3050:
3047:
3045:
3042:
3040:
3037:
3035:
3032:
3030:
3027:
3025:
3022:
3020:
3017:
3015:
3012:
3010:
3007:
3006:
3004:
3000:
2994:
2991:
2989:
2986:
2984:
2981:
2979:
2976:
2972:
2969:
2967:
2964:
2963:
2962:
2959:
2957:
2956:
2952:
2950:
2947:
2944:
2941:
2939:
2936:
2934:
2931:
2929:
2926:
2924:
2923:Smoke signals
2921:
2917:
2914:
2912:
2909:
2907:
2904:
2903:
2902:
2901:Semiconductor
2899:
2895:
2892:
2891:
2890:
2887:
2885:
2882:
2880:
2877:
2875:
2872:
2870:
2867:
2865:
2862:
2860:
2857:
2855:
2852:
2850:
2847:
2843:
2840:
2839:
2838:
2835:
2833:
2830:
2828:
2825:
2823:
2820:
2818:
2815:
2813:
2810:
2808:
2805:
2803:
2800:
2798:
2795:
2793:
2790:
2788:
2785:
2781:
2778:
2776:
2773:
2771:
2768:
2766:
2763:
2762:
2761:
2760:Digital media
2758:
2754:
2751:
2749:
2746:
2744:
2741:
2739:
2736:
2735:
2734:
2731:
2729:
2726:
2724:
2721:
2719:
2716:
2714:
2711:
2709:
2706:
2704:
2701:
2700:
2698:
2696:
2692:
2688:
2681:
2676:
2674:
2669:
2667:
2662:
2661:
2658:
2652:
2650:
2646:
2643:
2642:
2637:
2635:
2632:
2629:
2628:
2623:
2620:
2616:
2613:
2611:
2608:
2607:
2605:
2601:
2600:
2590:
2589:
2583:
2582:
2577:
2573:
2569:
2568:
2563:
2562:
2556:
2555:
2550:
2549:
2543:
2542:
2537:
2536:
2530:
2529:
2524:
2523:
2517:
2516:
2511:
2510:
2504:
2503:
2498:
2497:
2491:
2490:
2485:
2484:
2478:
2477:
2472:
2471:
2465:
2464:
2459:
2453:
2445:
2444:
2438:
2437:
2432:
2431:
2424:
2423:
2418:
2417:
2411:
2410:
2405:
2404:
2398:
2397:
2392:
2388:
2384:
2383:
2378:
2377:
2371:
2370:
2365:
2364:
2358:
2357:
2352:
2351:
2345:
2344:
2339:
2338:
2332:
2331:
2326:
2325:
2319:
2318:
2313:
2312:
2306:
2305:
2300:
2296:
2292:
2291:
2286:
2282:
2278:
2274:
2270:
2266:
2262:
2257:
2256:
2251:
2245:
2241:
2236:
2235:
2230:
2224:
2220:
2219:
2213:
2212:
2202:
2197:
2189:
2185:
2179:
2171:
2167:
2161:
2153:
2149:
2143:
2129:
2125:
2119:
2112:. 1922-08-10.
2111:
2104:
2098:
2083:
2079:
2073:
2059:
2055:
2049:
2042:
2038:
2035:
2030:
2016:
2012:
2005:
1991:
1987:
1981:
1973:
1967:
1963:
1959:
1952:
1946:
1944:
1935:
1931:
1927:
1921:
1906:
1902:
1896:
1888:
1884:
1877:
1863:
1859:
1852:
1850:
1835:
1831:
1825:
1823:
1814:
1808:
1804:
1803:
1795:
1781:
1777:
1771:
1765:
1760:
1745:
1739:
1732:
1728:
1724:
1718:
1703:
1701:9780313347436
1697:
1693:
1692:
1685:
1677:
1671:
1667:
1666:
1658:
1650:
1644:
1640:
1639:
1632:
1618:
1614:
1607:
1593:
1589:
1583:
1569:
1565:
1558:
1544:
1540:
1534:
1520:on 2021-04-17
1516:
1512:
1505:
1499:
1491:
1485:
1478:. 2020-10-23.
1474:
1468:
1466:
1464:
1448:
1444:
1438:
1424:
1417:
1411:
1406:
1400:
1395:
1379:
1372:
1364:
1362:9788184312829
1358:
1354:
1353:
1345:
1337:
1335:9780750626323
1331:
1327:
1326:
1318:
1310:
1308:9788122413397
1304:
1300:
1299:
1291:
1283:
1282:
1274:
1266:
1265:
1257:
1255:
1253:
1236:
1232:
1225:
1209:
1203:
1201:
1185:
1181:
1175:
1161:
1160:Atlas Obscura
1157:
1150:
1142:
1138:
1134:
1130:
1126:
1119:
1111:
1110:
1102:
1095:
1091:
1087:
1086:
1078:
1071:
1067:
1061:
1057:
1052:
1051:
1043:
1035:
1034:
1026:
1022:
1012:
1008:
1004:
1003:
990:
989:Radioteletype
987:
985:
982:
980:
977:
974:
971:
970:
960:
953:
948:
941:
936:
933:
926:
921:
918:
914:
910:
904:
899:
898:
892:
889:
884:
882:
878:
869:
867:
862:
860:
856:
853:
849:
845:
844:radioteletype
841:
837:
833:
829:
824:
820:
812:
807:
798:
796:
791:
786:
784:
780:
776:
772:
767:
764:
737:
733:
724:
715:
706:
697:
693:
671:
644:
635:
631:
627:
622:
620:
615:
613:
609:
605:
601:
597:
596:arc converter
592:
588:
584:
579:
577:
573:
569:
565:
555:
553:
549:
545:
544:telegraph key
541:
540:audio signals
537:
533:
529:
525:
520:
517:
516:Telegraph Act
513:
509:
505:
500:
495:
493:
488:
485:
481:
476:
474:
470:
466:
462:
458:
457:telegraph key
454:
450:
446:
442:
438:
429:
419:
416:
412:
405:
396:
392:
389:and receiver
388:
384:
377:
367:
363:
353:
351:
347:
343:
338:
334:
330:
329:amateur radio
326:
322:
318:
313:
311:
307:
303:
302:radio beacons
300:
296:
292:
288:
287:amateur radio
284:
280:
274:
272:
268:
264:
260:
256:
252:
251:telegraph key
248:
243:
241:
237:
236:radioteletype
233:
229:
225:
221:
218:
214:
210:
206:
202:
198:
194:
190:
186:
182:
181:on-off keying
178:
164:
152:
138:
136:
135:amateur radio
132:
128:
122:
120:
116:
112:
108:
104:
100:
96:
92:
87:
85:
81:
77:
76:telegraph key
73:
68:
64:
60:
56:
52:
48:
41:
37:
32:
19:
3419:Multiplexing
3294:Transmission
3259:Nikola Tesla
3249:Henry Sutton
3204:Samuel Morse
3134:Robert Hooke
3099:Amos Dolbear
3034:John Bardeen
2953:
2933:Telautograph
2837:Mobile phone
2792:Edholm's law
2775:social media
2708:Broadcasting
2648:
2640:
2626:
2603:
2587:
2575:
2560:
2547:
2534:
2521:
2508:
2495:
2482:
2469:
2442:
2428:
2415:
2402:
2390:
2375:
2362:
2349:
2336:
2323:
2310:
2298:
2268:
2264:
2239:
2217:
2196:
2187:
2178:
2169:
2160:
2151:
2142:
2131:. Retrieved
2127:
2118:
2109:
2097:
2086:. Retrieved
2084:. 2024-05-15
2081:
2072:
2061:. Retrieved
2057:
2048:
2029:
2018:. Retrieved
2014:
2004:
1993:. Retrieved
1989:
1980:
1961:
1957:
1934:the original
1920:
1909:. Retrieved
1907:. 2015-12-31
1904:
1895:
1886:
1876:
1865:. Retrieved
1861:
1837:. Retrieved
1833:
1801:
1794:
1783:. Retrieved
1779:
1770:
1759:
1748:. Retrieved
1738:
1722:
1717:
1705:. Retrieved
1690:
1684:
1664:
1657:
1637:
1631:
1620:. Retrieved
1616:
1606:
1595:. Retrieved
1591:
1582:
1571:. Retrieved
1567:
1557:
1546:. Retrieved
1543:www.elon.edu
1542:
1533:
1522:. Retrieved
1515:the original
1510:
1498:
1484:
1451:. Retrieved
1449:. 2021-04-01
1447:www.arrl.org
1446:
1437:
1426:. Retrieved
1416:
1405:
1394:
1382:. Retrieved
1371:
1351:
1344:
1324:
1317:
1297:
1290:
1280:
1273:
1263:
1239:. Retrieved
1234:
1224:
1212:. Retrieved
1188:. Retrieved
1186:. 2024-04-12
1183:
1174:
1163:. Retrieved
1159:
1149:
1124:
1118:
1108:
1101:
1093:
1084:
1077:
1069:
1049:
1042:
1032:
1025:
916:
912:
885:
875:
863:
832:broadcasting
816:
787:
768:
623:
619:carrier wave
616:
580:
561:
534:, primitive
523:
521:
496:
489:
477:
434:
417:
390:
386:
314:
275:
267:teleprinters
255:carrier wave
244:
240:World War II
220:carrier wave
205:damped waves
174:
123:
91:transmitters
88:
66:
50:
46:
45:
36:Signal Corps
3619:NPL network
3331:Radio waves
3269:Alfred Vail
3179:Hedy Lamarr
3164:Dawon Kahng
3124:Elisha Gray
3084:Yogen Dalal
3009:Nasir Ahmed
2943:Teleprinter
2807:Heliographs
2446:. New York.
2271:(1): 1–20.
1384:19 November
1214:19 November
932:World War I
790:World War I
568:damped wave
492:radio waves
310:identifiers
213:vacuum tube
103:World War I
80:transmitter
55:radio waves
3763:Telegraphy
3752:Categories
3665:Antarctica
3624:Toasternet
3546:Television
3029:Paul Baran
2961:Television
2945:(teletype)
2938:Telegraphy
2916:transistor
2894:Phryctoria
2864:Photophone
2842:Smartphone
2832:Mass media
2249:0471018163
2133:2024-05-23
2088:2024-05-23
2063:2024-05-21
2020:2024-05-21
1995:2024-05-23
1911:2024-05-23
1867:2024-05-21
1839:2024-05-21
1785:2024-05-21
1750:2012-04-15
1622:2024-05-22
1597:2024-05-22
1573:2024-05-22
1548:2024-05-22
1524:2021-05-06
1453:2021-05-08
1428:2021-05-08
1190:2024-05-17
1165:2024-05-17
1065:0877798095
872:Regulation
859:short wave
771:oscillator
696:heterodyne
528:Morse code
461:Morse code
411:Morse code
397:, May 1897
259:Morse code
217:sinusoidal
197:modulation
141:Principles
127:world wars
72:Morse code
40:New Guinea
34:A US Army
3649:Americas
3638:Locations
3609:Internet2
3370:Bandwidth
3074:Vint Cerf
2971:streaming
2949:Telephone
2889:Semaphore
2780:streaming
2452:cite book
2430:Operation
2285:0021-938X
2221:. Wiley.
1856:ID, FCC.
1731:655205099
1018:Citations
836:telegrams
734:−
576:bandwidth
548:earphones
455:called a
395:Flat Holm
350:call sign
249:called a
209:bandwidth
95:receivers
3717:Category
3604:Internet
3594:CYCLADES
3511:Ethernet
3461:Concepts
3385:terminal
3336:wireless
3159:Bob Kahn
3002:Pioneers
2827:Internet
2718:Cable TV
2037:Archived
1862:FCCID.io
1241:16 March
967:See also
801:Industry
626:detector
391:(bottom)
387:(center)
263:receiver
119:telegram
84:receiver
3737:Commons
3727:Outline
3680:Oceania
3599:FidoNet
3584:ARPANET
3397:circuit
2966:digital
2695:History
2154:. 1968.
1707:July 8,
1141:6928472
1000:General
913:(right)
895:Gallery
886:The US
558:Methods
465:battery
383:Marconi
356:History
222:called
191:, is a
3675:Europe
3645:Africa
3629:Usenet
3589:BITNET
3526:Mobile
3402:packet
2911:MOSFET
2906:device
2703:Beacon
2651:(1919)
2644:(1919)
2630:{1904}
2283:
2246:
2225:
1968:
1809:
1729:
1698:
1672:
1645:
1359:
1332:
1305:
1139:
1062:
917:(left)
473:ground
453:switch
418:(left)
247:switch
63:cables
61:using
3658:South
3653:North
3614:JANET
3551:Telex
3541:Radio
3380:Nodes
3375:Links
3296:media
2874:Radio
2859:Pager
2787:Drums
2753:video
2748:image
2738:audio
2106:(PDF)
1954:(PDF)
1518:(PDF)
1507:(PDF)
1476:(PDF)
1137:S2CID
866:GMDSS
852:CCITT
848:telex
572:hertz
552:radio
283:GMDSS
115:audio
109:(AM)
3670:Asia
3556:UUCP
3516:ISDN
2458:link
2281:ISSN
2244:ISBN
2223:ISBN
1966:ISBN
1807:ISBN
1727:OCLC
1709:2011
1696:ISBN
1670:ISBN
1643:ISBN
1386:2021
1357:ISBN
1330:ISBN
1303:ISBN
1243:2018
1216:2021
1060:ISBN
1056:1437
855:R.44
838:and
711:BEAT
610:and
594:the
364:and
346:CEPT
297:and
93:and
3561:WAN
3531:NGN
3521:LAN
2802:Fax
2743:DCT
2273:doi
1129:doi
1090:333
1009:",
773:by
742:BFO
649:BFO
393:on
333:FT8
299:NDB
291:KSM
187:as
49:or
3754::
2624:,
2606::
2574:.
2454:}}
2450:{{
2389:.
2297:.
2279:.
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