472:
spread spectrum, most being sold today are low-cost analog models, which are still susceptible to eavesdropping. Digital variants can still be scanned, but are received as a digital hiss and therefore are difficult to eavesdrop upon. Digital transmission is immune to static interference but can experience signal fade (brief silence) as the phone goes out of range of the base. Newer
Digital Spread Spectrum (DSS) variants spread their signal over a range of frequencies, providing more resistance to signal fade. This technology enabled the digital information to spread in pieces among several frequencies between the receiver and the base, thereby making it almost impossible to eavesdrop on the cordless conversation. The FCC only allows DSS model phones to transmit at the full power of 1 watt, which allows increased range over older analog and digital models.
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coupler, a crude device for interconnecting a two-way radio with the telephone, led to the reversal of the
Federal Communications Commission ban on direct coupling of consumer equipment to phone lines (known as the landmark Carterfone decision) on June 26, 1968. The original cordless phones, like the
378:
In 1994, digital cordless phones in the 900 MHz frequency range became available to consumers. These new types of phones provided better audio quality because it could filter out interference and its signals could penetrate walls more easily. Digital signals allowed the phones to be more secure
310:
receiver. Full supervision of all telephone functions, including on-off hook and dialing was provided via an out of band tone supervision system. The model developed for home use was designed to look like a standard (although bulky) telephone handset. The base station was a small box connected to a
301:
Beginning in 1963, a small team of Bell
Laboratories engineers were tasked with developing a practical and fully functional duplex wireless telephone. The team included (in alphabetic order): S.M. Baer, G.C. Balzer, J.M. Brown, W.F. Clemency, M. Rosenthal, and W. Zinsmeister, under the direction of
471:
900 MHz cordless phones are rarely sold but have a huge installed base. Features include even shorter antennas, up to 30 auto selecting channels, and higher resistance to interference. Available in several varieties; analog, analog spread spectrum (100 kHz bandwidth), digital, and digital
455:
43–50 MHz cordless phones had a large installed base by the early 1990s, and featured shorter flexible antennas and automatic channel selection. Due to their popularity, an overcrowding of the band led to an allocation of additional frequencies; thus manufacturers were able to sell models with
305:
By 1964, breadboard models were working in the lab. During 1964-65 these were refined and packaged to test around the Bell Labs
Holmdel N.J. facilities. The system operated under an experimental license on crystal controlled channels in the 35 and 43 MHz bands using FM, a low power transmitter
573:
is 3.6 kHz; only a fraction of the frequencies that humans can hear, but enough to make the voice intelligible. No phone handset can improve on this quality, as it is a limitation of the phone system itself. Higher-quality phones can transfer this signal to the handset with less interference
451:
band were selected manually by the user. Some of the frequencies used are now part of the expanded AM radio band, and can be heard by anyone with an AM radio. There are reports of people still using these phones, and using them as makeshift AM radio stations that can be heard for a couple of city
365:
for a duplex voice communication link including controls provided between a base station connected directly to a telephone line of a telephone exchange and a mobile unit consisting of a small, compact cordless telephone instrument containing transmitter, receiver and control circuits powered by a
443:
Over-crowding of earlier frequency allocations led users to discontinue using telephone equipment that operated on those frequencies, leaving those bands relatively clear. Radio hobbyists monitor usage of the older equipment with telephone activity in the US AM broadcast band, some 27 MHz
375:, the number of cordless phones sold in the United States grew from 50,000 in 1980 to 1 million in 1982. They quickly became popular because of their convenience and portability, despite fears that their reliance on radio signals would make them vulnerable to eavesdropping or other malfeasance.
530:
Many cordless phones in the 21st century are digital. Digital technology has helped provide clear sound and limit casual eavesdropping. Many cordless phones have one main base station and can add up to three or four additional bases. This allows for multiple voice channels that allow three-way
479:
on the 1.9 GHz band, though legacy phones can remain in use on the older 900 MHz, 2.4 GHz and 5.8 GHz bands. There is no specific requirement for any particular transmission mode on the older bands, but in practice many legacy phones also have digital features such as
1003:
Unlike wired telephones that are powered from the telephone company's central station batteries, a cordless phone base station required electrical power to operate. During a power interruption, the cordless base station will not be operable, while wired sets may continue to operate.
456:
25 channels instead of just 10 channels. Although less susceptible to interference than previous AM units, these models are no longer in production and are considered obsolete because their frequencies are easily heard on practically any radio scanner. Advanced models began to use
408:
1.7 MHz (1.665–1.770 MHz, narrow-band FM) Cordless phones manufactured after
October 1, 1984, are not allowed to use this band and were required to use the newer (higher) 43-50 MHz frequencies, although older telephones, on the older frequency pairs, could still be
506:), now use DECT 6.0. However, DECT 6.0's late start compared to DECT elsewhere has led to a large installed base of legacy cordless phones using other frequencies, many of which remain in use today despite increasingly common interference with the ever growing use of
311:
standard telephone network. About 50 units were built in a
Western Electric model shop in Andover Mass. for field trials in two Bell System locations in the Boston and Phoenix area. The overall project was described in the Bell Laboratories Record, Volume 45 (1967).
412:
27 MHz, near the
Citizens Band (CB) Radio service with some frequencies being 26.010, 26.050, 26.380, 26.419 and 27.095 MHz. These were initially paired with the 1.7 MHz frequencies, then, later, with the 49 MHz frequencies. Signals were
1420:
452:
blocks. These models became obsolete because they are susceptible to eavesdropping, and interference from fluorescent lighting and automobile ignition systems. However, under ideal conditions they could have 0.5 miles (0.80 km) or more range.
293:
went into service in 1946. Because the range was intended to cover the widest possible service area, capacity was extremely low, and the early tube technology made equipment rather large and heavy. The second generation radio telephone, or
1407:
679:
can decode the signal, and it chooses from one of thousands of such unique codes each time the handset is returned to the cradle. Additionally, the digital nature of the signal increases its tolerance to noise, and some systems even
574:
over a greater range, however. Most cordless telephones, no matter what frequency band or transmission method is used, will hardly ever exactly match the sound quality of a high-quality wired telephone attached to a good
648:, allowing anyone within range to listen in on conversations (though this is illegal in many countries). Though many such analog models are still produced, modern digital technology is available to reduce the risk of
383:(DSS) was introduced for cordless phones. This technology enabled the spreading of the digital voice transmission over multiple frequencies, improving privacy and reducing interference between different subscribers.
822:
Roaming cordless phone handsets exist which are not tethered to any particular base station, but which also do not use traditional mobile (cellular) phone networks. These most commonly use digital technologies like
617:; thus, it is likely that a cordless phone will suffer interference from signals broadcast by those devices, and also may itself generate interference. It is also possible for a cordless phone to interfere with the
1071:
1394:
831:/b/g standards-based wireless LAN technology. Analog equivalents do exist and can provide longer reach, but with potential loss of confidentiality and voice quality. The cordless phone handset connects to a
420:
43–50 MHz (Base: 43.72–46.97 MHz, Handset: 48.76–49.99 MHz, FM) Allocated in
December 1983, and approved for use in mid-1984 for 10 channels. 15 additional channels allocated April 5, 1995.
491:
Some cordless phones formerly advertised as 5.8 GHz actually transmit from base to phone on 5.8 GHz and transmit from phone to base on 2.4 GHz or 900 MHz, to conserve battery life.
538:
Manufacturers usually advertise that their higher frequency systems improve audio quality and range. In the ideal case, higher frequencies actually have worse signal propagation as shown by the basic
625:
standard can be configured to operate in the 5.8 GHz range. However, this can easily be fixed by reconfiguring the wireless LAN device to work in the 5.180 GHz to 5.320 GHz band.
522:
phone standard from its inception. DECT, on its
European band & related frequencies, has largely displaced all other cordless phone standards worldwide except for North America.
447:
1.7 MHz cordless phones were the earliest models available at retailers, and are generally identifiable by their large metal telescoping antennas. Channels just above the
343:-owned telephone lines in the late 1960s. The telephone companies at the time did not permit third-party equipment to be connected to their lines; most telephones were made by
1104:
498:
phone standard and is considered more secure than the other shared frequencies. The vast majority of new cordless phone devices sold in North
America, whether connected by
535:
between the bases. This technology also allows multiple handsets to be used at the same time, and up to two handsets can have separate conversations with outside parties.
598:
Most manufacturers claim a range of about 30 metres (98 ft) for their 2.4 GHz and 5.8 GHz systems, but inexpensive models often fall short of this claim.
1075:
2576:
366:
rechargeable battery pack. A single logic tone is transmitted and detected for all logical control for ring signals, on-hook and off-hook signals and dial pulses.
601:
However, the higher frequency often brings advantages. The 900 MHz and 2.4 GHz band are increasingly being used for a host of other devices, including
1781:
356:
588:
A noticeable amount of constant background noise (this is not interference from outside sources, but noise within the cordless telephone system)
94:
672:, yielding longer range and less susceptibility to interference. Higher frequency bands provide more room for these wide-bandwidth signals.
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in its limited range and by depending on the base station on the subscriber premises. Current cordless telephone standards, such as
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2250:
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868:
1615:
336:, developed the full duplex concept for untrained personnel, to improve battlefield communications for senior commanders.
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711:
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and decreased eavesdropping; it was relatively easy to eavesdrop on analog cordless phone conversations. In 1995 digital
56:
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17:
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are designed to transfer audio with a quality that is just adequate for the parties to understand each other. Typical
239:. The operational range is limited, usually to the same building or within some short distance from the base station.
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To an analog receiver like a scanner, a DSS signal sounds like bursts of noise. Only the base unit using a matching
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258:(handover); various advanced features, such as data-transfer; and even, on a limited scale, international
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Radio telephony (telephony without wires) predated cordless phones by at least two decades. The first,
2379:
2301:
2240:
1947:
510:, Bluetooth and other unlicensed digital radio standards, especially at 2.4 GHz and 5.8 GHz.
1418:, G. H. Sweigert, "Duplex Radio Communication and Signalling Apparatus", issued 1969-06-10
1415:
2151:
2112:
1957:
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to spread the audio signal (with a 3 kHz bandwidth) over a much wider range of frequencies in a
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1600:
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1.9 GHz (1920–1930 MHz, developed in 1993 and allocated in October 2005, especially with
328:
in June 1969. Sweigert, a radio operator in World War II stationed at the South Pacific Islands of
290:
254:, have blurred the once clear-cut line between cordless and mobile telephones by implementing cell
110:
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tends to increase at higher frequencies as well. Practical influences on quality and range are
369:
Cordless phones became widely used in home and workplaces during the early 1980s. According to
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5.8 GHz (5725–5875 MHz, allocated in 2003 due to crowding on the 2.4 GHz band)
2173:
1977:
1942:
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1842:
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669:
1506:
1093:
DUPLEX RADIO COMMUNICATION AND SIGNALING APPARATUS FOR PORTABLE TELEPHONE ... G. H. SWEIGERT
352:
Carterfone, were acoustically (not electrically) connected to the public telephone network.
102:
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2017:
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1709:
1531:
1317:"Cordless Telephone Systems - Wireless & Mobile Communications Questions & Answers"
414:
278:
8:
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2037:
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1541:
333:
968:
Please help update this article to reflect recent events or newly available information.
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Please help update this article to reflect recent events or newly available information.
160:
Please help update this article to reflect recent events or newly available information.
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2012:
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Sweigert was an active proponent for directly coupling consumer electronics to the
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points, thus using a broadband Internet connection to defer the connection to the
1997:
1852:
1620:
1595:
1583:
1292:"1.7MHz cordless telephone datasheet & application notes - Datasheet Archive"
1031:
645:
551:
547:
532:
464:. These phones share the 49.8 MHz band (49.830 - 49.890) with some wireless
457:
397:
380:
315:
1405:, ROBERTO LANDELL DE MOTYRA, "WIRELESS TELEPHONE", issued 1904-11-22
2195:
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2002:
1972:
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not being the full frequency response available in a wired landline telephone
461:
578:. This limitation is caused by a number of issues, including the following:
518:
In Europe, the 1.9 GHz (1880–1900 MHz) band was set aside for the
2222:
2062:
2007:
1937:
1902:
1837:
1736:
1726:
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836:
614:
602:
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232:
31:
281:, which the base station re-charges when the handset rests in its cradle.
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1982:
1967:
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The newer 1.9 GHz band is reserved for use by phones that use the
555:
348:
2412:
1877:
1692:
1459:
1366:
The Pocket Disaster Survival Guide: What to Do When the Lights Go Out
610:
543:
503:
2407:
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2314:
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1962:
633:
582:
566:
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427:
215:
A Panasonic KX-TG2226B 2.4GHz cordless phone with answering machine
195:
664:
way. Spreading the signal out over a wider bandwidth is a form of
2402:
2387:
1605:
841:
Also required is a call management function and a gateway to the
681:
622:
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433:
274:
259:
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228:
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may maintain base stations and users subscribe to the service.
845:(PSTN). This may or may not be integrated in the base-station.
2417:
2354:
1662:
507:
93:
deal primarily with the United States and do not represent a
2359:
856:
824:
629:
519:
251:
1455:
Information about Digital Spread-Spectrum cordless phones
460:
as a basic form of scrambling to help limit unauthorized
1392:, A. G. Bell, "Telegraph", issued 1876-03-07
644:
Many analog phone signals are easily picked up by radio
632:
standard, which should avoid interference issues in the
585:: hearing one's own voice echoed in the receiver speaker
1440:
Review of Frequency Allocations for Cordless Telephones
444:
frequencies and most older 43-50 MHz frequencies.
859:
to a remote gateway operated by the service provider.
269:
Unlike a corded telephone, a cordless telephone needs
475:
Virtually all new cordless phones sold in the US use
636:
900 MHz, 2.4 GHz, and 5.8 GHz bands.
423:900 MHz (902–928 MHz, allocated in 1993)
322:wireless communications apparatus". He was awarded
404:for uses that include cordless phones. These are:
242:A cordless telephone differs functionally from a
2577:Telecommunications-related introductions in 1965
2553:
851:service can be used by phones that use wireless
558:used, and interference, which varies locally.
27:Portable telephone that connects to a landline
1475:
1242:"Cordless Telephones Get Better, More Secure"
347:and leased to the customer by AT&T. The
91:The examples and perspective in this article
684:the digital signal for additional security.
513:
2490:Global telecommunications regulation bodies
907:Learn how and when to remove these messages
726:Learn how and when to remove these messages
71:Learn how and when to remove these messages
2526:
1482:
1468:
687:
296:IMTS, or Improved Mobile Telephone Service
273:(to power the base station). The cordless
991:Learn how and when to remove this message
810:Learn how and when to remove this message
183:Learn how and when to remove this message
129:Learn how and when to remove this message
1364:Harris J. Andrews, J. Alexander Bowers,
436:(2400–2500 MHz, allocated in 1998)
210:
202:
194:
1376:, chapter 2 "Preparing for a Blackout"
1109:Santa Clara High Technology Law Journal
1102:
827:, 2.4 GHz unlicensed spectrum, or
14:
2554:
1489:
1314:
1158:
318:submitted a patent application for a "
262:. In specialized models, a commercial
1463:
1267:"FCC Approves 25 Channels For Phones"
1192:trouble, staying nimble and dodging.
1161:"A New Generation Of Cordless Phones"
494:The 1.9 GHz band is used by the
2536:
1125:
948:
913:
872:
869:Wireless device radiation and health
862:
767:
732:
691:
140:
77:
36:
1191:
839:that supports the same technology.
24:
25:
2603:
1433:
1019:Fixed-Mobile Convergence Alliance
888:This section has multiple issues.
843:public switched telephone network
707:This section has multiple issues.
502:or to mobile phones (usually via
402:Federal Communications Commission
400:bands have been allocated by the
359:and L Duane Gregory were granted
52:This article has multiple issues.
2535:
2525:
2516:
2515:
2504:
2125:Free-space optical communication
953:
917:
877:
772:
736:
696:
391:
291:MTS, or Mobile Telephone Service
207:3 VTech cordless landline phones
145:
82:
41:
30:For mobile/cellular phones, see
1358:
1333:
1308:
1284:
1259:
1225:"Servicing Cordless Telephones"
1159:Elrich, David J. (1994-12-01).
896:or discuss these issues on the
715:or discuss these issues on the
60:or discuss these issues on the
1341:"How Cordless Telephones Work"
1234:
1218:
1185:
1152:
1119:
1096:
1082:
1064:
1051:"How Cordless Telephones Work"
1043:
525:
386:
13:
1:
1231:, May 1985, pages 77-80, 118.
1128:"CORDLESS PHONES CATCHING ON"
1037:
2592:Projects established in 1965
2511:Telecommunication portal
2292:Telecommunications equipment
1450:How Cordless Telephones Work
396:In the United States, seven
231:that connects by radio to a
7:
2587:Products introduced in 1965
2028:Alexander Stepanovich Popov
1368:, Simon and Schuster, 2010
1273:. April 6, 1995. p. 8B
1255:– via Newspapers.com.
1248:. May 19, 1985. p. D-6
1026:Personal Handy-phone System
1007:
639:
563:Plain old telephone service
540:Friis transmission equation
105:, discuss the issue on the
10:
2608:
1732:Telecommunications history
1382:
1126:Kerr, Peter (1983-02-16).
1103:Johnson, Nicholas (2009).
866:
621:wireless standard, as the
284:
29:
2499:
2441:
2378:
2340:Public Switched Telephone
2300:
2264:
2221:
2162:
2152:telecommunication circuit
2113:Fiber-optic communication
2096:
1858:Francis Blake (telephone)
1805:
1653:Optical telecommunication
1497:
1414:
1401:
1388:
962:This section needs to be
781:This section needs to be
514:Outside the United States
415:FM - frequency modulation
227:has a portable telephone
154:This article needs to be
2251:Orbital angular-momentum
1688:Satellite communications
1527:Communications satellite
1296:www.datasheetarchive.com
1028:(PHS) in Japan and China
235:connected to the public
2130:Molecular communication
1953:Gardiner Greene Hubbard
1782:Undersea telegraph line
1517:Cable protection system
688:Cordless phone handsets
654:Digital Spread Spectrum
554:quality, the method of
298:became active in 1964.
264:mobile network operator
199:Two cordless telephones
2272:Communication protocol
2058:Charles Sumner Tainter
1873:Walter Houser Brattain
1818:Edwin Howard Armstrong
1626:Information revolution
1105:"Carterfone: My Story"
1072:"Telephone Collectors"
216:
208:
200:
2246:Polarization-division
1978:Narinder Singh Kapany
1943:Erna Schneider Hoover
1863:Jagadish Chandra Bose
1843:Alexander Graham Bell
1574:online video platform
1416:US patent 3449750
1315:bhojas (2018-04-24).
1227:by Christopher Kite,
1090:U.S. patent 3,449,750
833:wireless access point
670:signal-to-noise ratio
656:(DSS) typically uses
362:U.S. patent 4,039,760
325:U.S. patent 3,449,750
214:
206:
198:
2567:Consumer electronics
2088:Vladimir K. Zworykin
2048:Almon Brown Strowger
2018:Charles Grafton Page
1673:Prepaid mobile phone
1601:Electrical telegraph
1445:Carterphone Decision
1403:US patent 775337
1390:US patent 174465
668:, and increases the
279:rechargeable battery
111:create a new article
103:improve this article
2572:American inventions
2562:Telephony equipment
2038:Johann Philipp Reis
1797:Wireless revolution
1759:The Telephone Cases
1616:Hydraulic telegraph
677:pseudorandom number
2582:1965 in technology
2236:Frequency-division
2213:Telephone exchange
2083:Charles Wheatstone
2013:Jun-ichi Nishizawa
1988:Innocenzo Manzetti
1923:Reginald Fessenden
1658:Optical telegraphy
1491:Telecommunications
1165:The New York Times
1132:The New York Times
929:. You can help by
748:. You can help by
592:Frequency response
372:The New York Times
302:W.D. Goodale, Jr.
225:portable telephone
221:cordless telephone
217:
209:
201:
18:Cordless telephony
2549:
2548:
2287:Store and forward
2282:Data transmission
2196:Network switching
2147:Transmission line
1993:Guglielmo Marconi
1958:Internet pioneers
1823:Mohamed M. Atalla
1792:Whistled language
1246:The Post-Crescent
1229:Radio-Electronics
1001:
1000:
993:
983:
982:
947:
946:
911:
863:Health and safety
820:
819:
812:
802:
801:
766:
765:
730:
658:frequency hopping
357:Douglas G. Talley
271:mains electricity
237:telephone network
193:
192:
185:
175:
174:
139:
138:
131:
113:, as appropriate.
75:
16:(Redirected from
2599:
2539:
2538:
2529:
2528:
2519:
2518:
2509:
2508:
2507:
2380:Notable networks
2370:Wireless network
2310:Cellular network
2302:Types of network
2277:Computer network
2164:Network topology
2078:Thomas A. Watson
1933:Oliver Heaviside
1918:Philo Farnsworth
1893:Daniel Davis Jr.
1868:Charles Bourseul
1828:John Logie Baird
1537:Data compression
1532:Computer network
1484:
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1179:
1156:
1150:
1149:
1147:
1146:
1123:
1117:
1116:
1100:
1094:
1092:
1086:
1080:
1079:
1074:. Archived from
1068:
1062:
1061:
1059:
1058:
1047:
996:
989:
978:
975:
969:
957:
956:
949:
942:
939:
921:
914:
903:
881:
880:
873:
846:
815:
808:
797:
794:
788:
776:
775:
768:
761:
758:
740:
733:
722:
700:
699:
692:
533:conference calls
364:
345:Western Electric
327:
306:and a sensitive
244:mobile telephone
188:
181:
170:
167:
161:
149:
148:
141:
134:
127:
123:
120:
114:
86:
85:
78:
67:
45:
44:
37:
21:
2607:
2606:
2602:
2601:
2600:
2598:
2597:
2596:
2552:
2551:
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2545:
2505:
2503:
2495:
2437:
2374:
2296:
2260:
2217:
2166:
2158:
2099:
2092:
1998:Robert Metcalfe
1853:Tim Berners-Lee
1801:
1621:Information Age
1493:
1488:
1436:
1421:
1408:
1395:
1385:
1380:
1363:
1359:
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1339:
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1323:
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1276:
1274:
1265:
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1260:
1251:
1249:
1240:
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1235:
1223:
1219:
1210:
1208:
1190:
1186:
1177:
1175:
1157:
1153:
1144:
1142:
1124:
1120:
1101:
1097:
1088:
1087:
1083:
1070:
1069:
1065:
1056:
1054:
1049:
1048:
1044:
1040:
1032:Spread spectrum
1010:
997:
986:
985:
984:
979:
973:
970:
967:
958:
954:
943:
937:
934:
927:needs expansion
882:
878:
871:
865:
840:
816:
805:
804:
803:
798:
792:
789:
786:
777:
773:
762:
756:
753:
746:needs expansion
701:
697:
690:
642:
548:signal strength
528:
516:
458:voice inversion
394:
389:
381:spread spectrum
360:
323:
316:George Sweigert
287:
189:
178:
177:
176:
171:
165:
162:
159:
150:
146:
135:
124:
118:
115:
100:
87:
83:
46:
42:
35:
28:
23:
22:
15:
12:
11:
5:
2605:
2595:
2594:
2589:
2584:
2579:
2574:
2569:
2564:
2547:
2546:
2544:
2543:
2533:
2523:
2513:
2500:
2497:
2496:
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2471:
2466:
2465:
2464:
2459:
2451:
2445:
2443:
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2430:
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2420:
2415:
2410:
2405:
2400:
2395:
2390:
2384:
2382:
2376:
2375:
2373:
2372:
2367:
2362:
2357:
2352:
2347:
2342:
2337:
2332:
2327:
2322:
2317:
2312:
2306:
2304:
2298:
2297:
2295:
2294:
2289:
2284:
2279:
2274:
2268:
2266:
2262:
2261:
2259:
2258:
2253:
2248:
2243:
2238:
2233:
2231:Space-division
2227:
2225:
2219:
2218:
2216:
2215:
2210:
2209:
2208:
2203:
2193:
2192:
2191:
2181:
2176:
2170:
2168:
2160:
2159:
2157:
2156:
2155:
2154:
2144:
2143:
2142:
2132:
2127:
2122:
2121:
2120:
2110:
2104:
2102:
2094:
2093:
2091:
2090:
2085:
2080:
2075:
2070:
2068:Camille Tissot
2065:
2060:
2055:
2050:
2045:
2043:Claude Shannon
2040:
2035:
2033:Tivadar Puskás
2030:
2025:
2020:
2015:
2010:
2005:
2003:Antonio Meucci
2000:
1995:
1990:
1985:
1980:
1975:
1973:Charles K. Kao
1970:
1965:
1960:
1955:
1950:
1948:Harold Hopkins
1945:
1940:
1935:
1930:
1925:
1920:
1915:
1910:
1905:
1900:
1895:
1890:
1885:
1880:
1875:
1870:
1865:
1860:
1855:
1850:
1848:Emile Berliner
1845:
1840:
1835:
1830:
1825:
1820:
1815:
1809:
1807:
1803:
1802:
1800:
1799:
1794:
1789:
1787:Videotelephony
1784:
1779:
1778:
1777:
1772:
1762:
1755:
1750:
1744:
1739:
1734:
1729:
1724:
1723:
1722:
1717:
1712:
1702:
1701:
1700:
1690:
1685:
1683:Radiotelephone
1680:
1675:
1670:
1665:
1660:
1655:
1650:
1649:
1648:
1638:
1633:
1628:
1623:
1618:
1613:
1608:
1603:
1598:
1593:
1588:
1587:
1586:
1581:
1576:
1571:
1569:Internet video
1561:
1560:
1559:
1554:
1549:
1544:
1534:
1529:
1524:
1519:
1514:
1509:
1503:
1501:
1495:
1494:
1487:
1486:
1479:
1472:
1464:
1458:
1457:
1452:
1447:
1442:
1435:
1434:External links
1432:
1431:
1430:
1425:
1412:
1399:
1384:
1381:
1379:
1378:
1357:
1332:
1307:
1283:
1271:Newspapers.com
1258:
1233:
1217:
1184:
1151:
1118:
1095:
1081:
1078:on 2016-04-03.
1063:
1041:
1039:
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1035:
1034:
1029:
1022:
1021:
1016:
1009:
1006:
999:
998:
981:
980:
961:
959:
952:
945:
944:
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922:
912:
886:
885:
883:
876:
867:Main article:
864:
861:
818:
817:
800:
799:
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778:
771:
764:
763:
743:
741:
731:
705:
704:
702:
695:
689:
686:
641:
638:
607:microwave oven
596:
595:
589:
586:
576:telephone line
527:
524:
515:
512:
441:
440:
437:
431:
424:
421:
418:
410:
393:
390:
388:
385:
286:
283:
191:
190:
173:
172:
153:
151:
144:
137:
136:
97:of the subject
95:worldwide view
90:
88:
81:
76:
50:
49:
47:
40:
26:
9:
6:
4:
3:
2:
2604:
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2318:
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2305:
2303:
2299:
2293:
2290:
2288:
2285:
2283:
2280:
2278:
2275:
2273:
2270:
2269:
2267:
2263:
2257:
2256:Code-division
2254:
2252:
2249:
2247:
2244:
2242:
2241:Time-division
2239:
2237:
2234:
2232:
2229:
2228:
2226:
2224:
2220:
2214:
2211:
2207:
2204:
2202:
2199:
2198:
2197:
2194:
2190:
2187:
2186:
2185:
2182:
2180:
2177:
2175:
2172:
2171:
2169:
2167:and switching
2165:
2161:
2153:
2150:
2149:
2148:
2145:
2141:
2138:
2137:
2136:
2133:
2131:
2128:
2126:
2123:
2119:
2118:optical fiber
2116:
2115:
2114:
2111:
2109:
2108:Coaxial cable
2106:
2105:
2103:
2101:
2095:
2089:
2086:
2084:
2081:
2079:
2076:
2074:
2071:
2069:
2066:
2064:
2061:
2059:
2056:
2054:
2051:
2049:
2046:
2044:
2041:
2039:
2036:
2034:
2031:
2029:
2026:
2024:
2023:Radia Perlman
2021:
2019:
2016:
2014:
2011:
2009:
2006:
2004:
2001:
1999:
1996:
1994:
1991:
1989:
1986:
1984:
1981:
1979:
1976:
1974:
1971:
1969:
1966:
1964:
1961:
1959:
1956:
1954:
1951:
1949:
1946:
1944:
1941:
1939:
1936:
1934:
1931:
1929:
1926:
1924:
1921:
1919:
1916:
1914:
1913:Lee de Forest
1911:
1909:
1908:Thomas Edison
1906:
1904:
1901:
1899:
1898:Donald Davies
1896:
1894:
1891:
1889:
1886:
1884:
1883:Claude Chappe
1881:
1879:
1876:
1874:
1871:
1869:
1866:
1864:
1861:
1859:
1856:
1854:
1851:
1849:
1846:
1844:
1841:
1839:
1836:
1834:
1831:
1829:
1826:
1824:
1821:
1819:
1816:
1814:
1811:
1810:
1808:
1804:
1798:
1795:
1793:
1790:
1788:
1785:
1783:
1780:
1776:
1773:
1771:
1768:
1767:
1766:
1763:
1761:
1760:
1756:
1754:
1751:
1748:
1745:
1743:
1740:
1738:
1735:
1733:
1730:
1728:
1727:Smoke signals
1725:
1721:
1718:
1716:
1713:
1711:
1708:
1707:
1706:
1705:Semiconductor
1703:
1699:
1696:
1695:
1694:
1691:
1689:
1686:
1684:
1681:
1679:
1676:
1674:
1671:
1669:
1666:
1664:
1661:
1659:
1656:
1654:
1651:
1647:
1644:
1643:
1642:
1639:
1637:
1634:
1632:
1629:
1627:
1624:
1622:
1619:
1617:
1614:
1612:
1609:
1607:
1604:
1602:
1599:
1597:
1594:
1592:
1589:
1585:
1582:
1580:
1577:
1575:
1572:
1570:
1567:
1566:
1565:
1564:Digital media
1562:
1558:
1555:
1553:
1550:
1548:
1545:
1543:
1540:
1539:
1538:
1535:
1533:
1530:
1528:
1525:
1523:
1520:
1518:
1515:
1513:
1510:
1508:
1505:
1504:
1502:
1500:
1496:
1492:
1485:
1480:
1478:
1473:
1471:
1466:
1465:
1462:
1456:
1453:
1451:
1448:
1446:
1443:
1441:
1438:
1437:
1429:
1426:
1417:
1413:
1404:
1400:
1391:
1387:
1386:
1375:
1371:
1367:
1361:
1346:
1345:HowStuffWorks
1342:
1336:
1322:
1318:
1311:
1297:
1293:
1287:
1272:
1268:
1262:
1247:
1243:
1237:
1230:
1226:
1221:
1207:
1203:
1199:
1195:
1188:
1174:
1170:
1166:
1162:
1155:
1141:
1137:
1133:
1129:
1122:
1115:(3): 677–700.
1114:
1110:
1106:
1099:
1091:
1085:
1077:
1073:
1067:
1052:
1046:
1042:
1033:
1030:
1027:
1024:
1023:
1020:
1017:
1015:
1012:
1011:
1005:
995:
992:
977:
965:
960:
951:
950:
941:
932:
928:
925:This section
923:
920:
916:
915:
910:
908:
901:
900:
895:
894:
889:
884:
875:
874:
870:
860:
858:
854:
850:
849:Voice over IP
844:
838:
834:
830:
826:
814:
811:
796:
784:
779:
770:
769:
760:
751:
747:
744:This section
742:
739:
735:
734:
729:
727:
720:
719:
714:
713:
708:
703:
694:
693:
685:
683:
678:
673:
671:
667:
663:
659:
655:
651:
650:eavesdropping
647:
637:
635:
631:
626:
624:
620:
616:
612:
608:
604:
599:
593:
590:
587:
584:
581:
580:
579:
577:
572:
568:
564:
559:
557:
553:
549:
545:
541:
536:
534:
523:
521:
511:
509:
505:
501:
497:
492:
489:
487:
483:
478:
473:
469:
467:
466:baby monitors
463:
462:eavesdropping
459:
453:
450:
445:
438:
435:
432:
429:
425:
422:
419:
416:
411:
407:
406:
405:
403:
399:
392:United States
384:
382:
376:
374:
373:
367:
363:
358:
353:
350:
346:
342:
337:
335:
331:
326:
321:
317:
312:
309:
303:
299:
297:
292:
282:
280:
276:
272:
267:
265:
261:
257:
253:
249:
245:
240:
238:
234:
230:
226:
222:
213:
205:
197:
187:
184:
169:
157:
152:
143:
142:
133:
130:
122:
112:
108:
104:
98:
96:
89:
80:
79:
74:
72:
65:
64:
59:
58:
53:
48:
39:
38:
33:
19:
2223:Multiplexing
2098:Transmission
2063:Nikola Tesla
2053:Henry Sutton
2008:Samuel Morse
1938:Robert Hooke
1903:Amos Dolbear
1838:John Bardeen
1757:
1737:Telautograph
1641:Mobile phone
1596:Edholm's law
1579:social media
1512:Broadcasting
1428:Patents Link
1365:
1360:
1349:. Retrieved
1347:. 2000-12-11
1344:
1335:
1324:. Retrieved
1320:
1310:
1299:. Retrieved
1295:
1286:
1275:. Retrieved
1270:
1261:
1250:. Retrieved
1245:
1236:
1228:
1220:
1209:. Retrieved
1197:
1187:
1176:. Retrieved
1164:
1154:
1143:. Retrieved
1131:
1121:
1112:
1108:
1098:
1084:
1076:the original
1066:
1055:. Retrieved
1053:. 2000-12-11
1045:
1002:
987:
971:
963:
935:
931:adding to it
926:
904:
897:
891:
890:Please help
887:
837:base station
821:
806:
790:
782:
757:October 2014
754:
750:adding to it
745:
723:
716:
710:
709:Please help
706:
674:
662:pseudorandom
643:
627:
615:wireless LAN
603:baby monitor
600:
597:
560:
537:
529:
517:
493:
490:
474:
470:
454:
449:AM broadcast
446:
442:
434:2.4 GHz
395:
377:
370:
368:
354:
338:
334:Bougainville
313:
307:
304:
300:
288:
268:
241:
233:base station
224:
220:
218:
179:
163:
155:
125:
116:
92:
68:
61:
55:
54:Please help
51:
32:Mobile phone
2423:NPL network
2135:Radio waves
2073:Alfred Vail
1983:Hedy Lamarr
1968:Dawon Kahng
1928:Elisha Gray
1888:Yogen Dalal
1813:Nasir Ahmed
1747:Teleprinter
1611:Heliographs
1194:"Geek Page"
853:data access
526:Performance
387:Frequencies
330:Guadalcanal
320:full duplex
277:contains a
2556:Categories
2469:Antarctica
2428:Toasternet
2350:Television
1833:Paul Baran
1765:Television
1749:(teletype)
1742:Telegraphy
1720:transistor
1698:Phryctoria
1668:Photophone
1646:Smartphone
1636:Mass media
1374:151072043X
1351:2021-03-23
1326:2021-03-23
1321:Sanfoundry
1301:2021-03-23
1277:2017-08-24
1252:2017-08-24
1211:2022-06-06
1178:2022-06-06
1145:2022-06-06
1057:2017-08-16
1038:References
1014:Carterfone
893:improve it
712:improve it
666:redundancy
634:unlicensed
556:modulation
349:Carterfone
119:March 2012
57:improve it
2453:Americas
2442:Locations
2413:Internet2
2174:Bandwidth
1878:Vint Cerf
1775:streaming
1753:Telephone
1693:Semaphore
1584:streaming
1206:1059-1028
1173:0362-4331
1140:0362-4331
899:talk page
718:talk page
611:Bluetooth
571:bandwidth
567:landlines
565:" (POTS)
544:path loss
504:Bluetooth
398:frequency
355:In 1977,
314:In 1966,
107:talk page
63:talk page
2521:Category
2408:Internet
2398:CYCLADES
2315:Ethernet
2265:Concepts
2189:terminal
2140:wireless
1963:Bob Kahn
1806:Pioneers
1631:Internet
1522:Cable TV
1008:See also
974:May 2023
938:May 2023
793:May 2023
646:scanners
640:Security
583:Sidetone
500:landline
496:DECT 6.0
477:DECT 6.0
428:DECT 6.0
341:AT&T
308:superhet
166:May 2023
101:You may
2541:Commons
2531:Outline
2484:Oceania
2403:FidoNet
2388:ARPANET
2201:circuit
1770:digital
1499:History
1383:Patents
964:updated
829:802.11a
783:updated
682:encrypt
623:802.11a
619:802.11a
552:antenna
285:History
275:handset
260:roaming
256:handoff
229:handset
156:updated
2479:Europe
2449:Africa
2433:Usenet
2393:BITNET
2330:Mobile
2206:packet
1715:MOSFET
1710:device
1507:Beacon
1422:
1409:
1396:
1372:
1204:
1171:
1138:
613:, and
542:, and
2462:South
2457:North
2418:JANET
2355:Telex
2345:Radio
2184:Nodes
2179:Links
2100:media
1678:Radio
1663:Pager
1591:Drums
1557:video
1552:image
1542:audio
1198:Wired
508:Wi-Fi
409:used.
109:, or
2474:Asia
2360:UUCP
2320:ISDN
1370:ISBN
1202:ISSN
1169:ISSN
1136:ISSN
857:PSTN
825:DECT
630:DECT
520:DECT
486:FHSS
484:and
482:DSSS
332:and
252:DECT
250:and
2365:WAN
2335:NGN
2325:LAN
1606:Fax
1547:DCT
933:.
835:or
752:.
248:PHS
223:or
2558::
1343:.
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847:A
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609:,
605:,
550:,
488:.
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219:A
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