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1974:
38:
1984:
2236:
1963:
1994:
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dedicated to provisioning of PSTN services. The agency regulate technical standards, legal requirements, and set service tasks may be for example to ensure that end customers are not over-charged for services where monopolies may exist. These regulatory agencies may also regulate the prices charged
240:
Commercialization of the telephone began shortly after its invention, with instruments operated in pairs for private use between two locations. Users who wanted to communicate with persons at multiple locations had as many telephones as necessary for the purpose. Alerting another user of the desire
444:
A key concept was that the telephone exchanges are arranged into hierarchies, so that if a call cannot be handled in a local cluster, it is passed to one higher up for onward routing. This reduced the number of connecting trunks required between operators over long distances, and also kept local
440:
The architecture of the PSTN evolved over time to support an increasing number of subscribers, call volume, destinations, features, and technologies. The principles developed in North
America and in Europe were adopted by other nations, with adaptations for local markets.
539:(E1) line used in most other countries. In modern networks, the multiplexing function is moved as close to the end user as possible, usually into cabinets at the roadside in residential areas, or into large business premises.
294:
established the mathematical foundations of methods required to determine the capacity requirements and configuration of equipment and the number of personnel required to deliver a specific level of service.
398:
In some countries, however, the job of providing telephone networks fell to government as the investment required was very large and the provision of telephone service was increasingly becoming an essential
370:
Several large private telephone networks are not linked to the PSTN, usually for military purposes. There are also private networks run by large companies that are linked to the PSTN only through limited
313:
In the 1980s, the industry began planning for digital services assuming they would follow much the same pattern as voice services and conceived end-to-end circuit-switched services, known as the
633:
Several other
European countries, including Estonia, Germany, Iceland, the Netherlands, Spain and Portugal, have also retired, or are planning to retire, their PSTN networks.
55:
569:, is of more general interest. This is the reference point between a primary multiplexer and an exchange. The protocols at this reference point were standardized in
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At the turn of the 21st century, the oldest parts of the telephone network still used analog baseband technology to deliver audio-frequency connectivity over the
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1946:
1918:
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As of 2023, operators worldwide are in the process of retiring support for both last-mile analog telephony and ISDN, and transitioning voice service to
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were installed between exchanges. Networks were designed in a hierarchical manner until they spanned cities, states, and international distances.
102:
1940:
650:
74:
1935:
1925:
1905:
1707:
489:. The call is then transmitted from one end to another via telephone exchanges. The call is switched using a call set up protocol (usually
267:
between the telephone and the exchange so that each subscriber could directly dial another subscriber connected to the same exchange, but
81:
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2130:
2030:
1930:
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819:
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Later telephone systems took advantage of the exchange principle already employed in telegraph networks. Each telephone was wired to a
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was accomplished by whistling loudly into the transmitter until the other party heard the alert. Bells were soon added to stations for
1702:
542:
These aggregated circuits are conveyed from the initial multiplexer to the exchange over a set of equipment collectively known as the
589:'s TIA-TSB-116 standard on voice-quality recommendations for IP telephony, to determine acceptable levels of audio latency and echo.
121:
88:
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59:
1712:
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555:
367:, eliminating the expense and complexity of running two separate technology infrastructures for PSTN and Internet access.
147:
1997:
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across multiple exchanges required manual switching by operators. Later, more sophisticated address signaling, including
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protocol transported over much of the end-to-end equipment as was already in use in the PSTN. These became known as
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1404:
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The access network defines a number of reference points. Most of these are of interest mainly to ISDN but one, the
521:
775:
48:
2120:
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618:, with an original completion date of December 2025, although this has now been put back to January 2027. See
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were progressively deployed in this portion of the network, primarily to provide high-speed
Internet access.
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2023:
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Most automated telephone exchanges use digital switching rather than mechanical or analog switching. The
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142:) is the aggregate of the world's telephone networks that are operated by national, regional, or local
212:. These standards have their origins in the development of local telephone networks, primarily in the
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standards, as with current mobile telephony, with the interface to end-users remaining the same.
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17:
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signaling methods, enabled direct-dialed long-distance calls by subscribers, culminating in the
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The technical operation of the PSTN adheres to the standards internationally promulgated by the
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and includes mobile and wireless networks, all of which are currently transitioning to use the
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2089:
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225:
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776:"The privatisation of British Telecom: A case study of the extended process of legislation"
279:(SS7) network that controlled calls between most exchanges by the end of the 20th century.
190:, and international gateways, which allow telephone users to communicate with each other.
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2058:
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1309:
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In the United
Kingdom, the copper POTS and ISDN-based PSTN is being retired in favour of
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connecting the exchanges are also digital, called circuits or channels. However analog
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in the United
Kingdom brought together a number of private companies to form a single
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411:. In more recent decades, these state monopolies were broken up or sold off through
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1679:
1519:
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1394:
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1183:
1035:
870:"What the UK can learn from the rest of the world when it comes to the shift to IP"
666:
574:
474:
345:
198:
688:"What Are the Public Switched Telephone Networks, 'PSTN' and Why You Should Care?"
585:
Voice quality in PSTN networks was used as a benchmark for the development of the
2171:
1879:
1529:
1439:
1424:
1384:
1344:
1203:
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The task of building the networks and selling services to customers fell to the
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535:(T1) line, or 32 DS0s (30 for calls plus two for framing and signaling) on an
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264:
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established for a town or area. For communication outside this exchange area,
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Countries in other continents are also performing similar transitions.
391:. The first company to be incorporated to provide PSTN services was the
1859:
1844:
216:
in the United States and in the networks of
European ITU members. The
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1171:
963:
916:
501:
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traffic separate. Modern technologies have brought simplifications
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1811:
1119:
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623:
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217:
209:
298:
In the 1970s, the telecommunications industry began implementing
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from the exchange to the telephone in the home (also called the
337:
303:
2012:
920:
719:"No Dialtone: The End of the Public Switched Telephone Network"
232:
allows telephones around the world to connect with each other.
2202:
1062:
531:(DS1) circuit carries 24 DS0s on a North American or Japanese
228:. The combination of the interconnected networks and a global
197:
telephone systems, the PSTN is almost entirely digital in its
31:
524:(TDM) equipment to form higher capacity communication links.
2008:
558:(SDH) technologies, although some parts still use the older
481:
with 8-bit resolution using a special type of nonlinear
477:, the analog audio signal is digitized at an 8 kHz
332:
to the end-user. However, digital technologies such as
546:. The access network and inter-exchange transport use
774:
Moon, Jeremy; Richardson, J.J.; Smart, Paul (1986).
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2082:
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1721:
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1619:
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1262:
954:
512:(DS0). The DS0 circuit is the basic granularity of
493:) between the telephone exchanges under an overall
62:. Unsourced material may be challenged and removed.
516:in a telephone exchange. A DS0 is also known as a
317:(B-ISDN). The B-ISDN vision was overtaken by the
842:"Global Learnings For The PSTN Switch Off | Yay"
864:
862:
752:Information sheets and timelines. Privatisation
622:. Voice telephony will continue to follow the
2024:
932:
500:The call is carried over the PSTN using a 64
315:Broadband Integrated Services Digital Network
8:
1947:Global telecommunications regulation bodies
2031:
2017:
2009:
1983:
939:
925:
917:
27:Aggregate of all public telephone networks
355:via Internet access delivered either via
122:Learn how and when to remove this message
895:"NiĂ°urlagning koparheimtaugakerfis MĂlu"
597:In most countries, the government has a
469:). To carry a typical phone call from a
816:Telecommunications Industry Association
678:
587:Telecommunications Industry Association
780:European Journal of Political Research
651:Managed facilities-based voice network
282:The growth of the PSTN was enabled by
698:from the original on 13 December 2019
7:
1993:
508:. The name given to this channel is
310:, or public switched data networks.
60:adding citations to reliable sources
550:optical transmission, for example,
193:Originally a network of fixed-line
71:"Public switched telephone network"
792:10.1111/j.1475-6765.1986.tb00839.x
686:Kushnick, Bruce (7 January 2013).
290:(QoS) in the network. The work of
220:standard provides a single global
25:
136:public switched telephone network
18:Public Switched Telephone Network
2244:
2234:
1992:
1982:
1973:
1972:
1961:
1582:Free-space optical communication
822:from the original on 8 July 2017
504:channel, originally designed by
36:
520:because DS0s are aggregated in
47:needs additional citations for
620:United Kingdom PSTN switch-off
461:are still used to connect the
1:
763:British Telecom Privatisation
646:List of country calling codes
556:Synchronous Digital Hierarchy
205:to carry their PSTN traffic.
2241:Telecommunication portal
1968:Telecommunication portal
1749:Telecommunications equipment
430:Routing in cellular networks
1485:Alexander Stepanovich Popov
661:Plain old telephone service
2296:
2275:Telecommunications systems
1189:Telecommunications history
717:Werbach, Kevin D. (2013).
604:carry each other's traffic
522:time-division multiplexing
433:
427:
2231:
2116:Communications satellites
1956:
1797:Public Switched Telephone
1609:telecommunication circuit
1570:Fiber-optic communication
1315:Francis Blake (telephone)
1110:Optical telecommunication
602:between the operators to
176:undersea telephone cables
172:communications satellites
1708:Orbital angular-momentum
1145:Satellite communications
984:Communications satellite
302:data services using the
230:telephone numbering plan
150:and services for public
2111:Cable protection system
1587:Molecular communication
1410:Gardiner Greene Hubbard
1239:Undersea telegraph line
974:Cable protection system
723:SSRN Electronic Journal
377:private branch exchange
300:packet-switched network
284:teletraffic engineering
154:. The PSTN consists of
146:operators. It provides
1729:Communication protocol
1515:Charles Sumner Tainter
1330:Walter Houser Brattain
1275:Edwin Howard Armstrong
1083:Information revolution
581:Impact on IP standards
395:in the United States.
393:Bell Telephone Company
286:techniques to deliver
263:Automation introduced
164:microwave transmission
2251:Telephones portal
1703:Polarization-division
1435:Narinder Singh Kapany
1400:Erna Schneider Hoover
1320:Jagadish Chandra Bose
1300:Alexander Graham Bell
1031:online video platform
483:pulse-code modulation
436:PSTN network topology
365:fiber-to-the-premises
319:disruptive technology
269:long-distance calling
2213:Telephone newspapers
1545:Vladimir K. Zworykin
1505:Almon Brown Strowger
1475:Charles Grafton Page
1130:Prepaid mobile phone
1058:Electrical telegraph
731:10.2139/ssrn.2241658
409:nationalized company
308:public data networks
56:improve this article
2136:Mobile phone signal
1495:Johann Philipp Reis
1254:Wireless revolution
1216:The Telephone Cases
1073:Hydraulic telegraph
405:General Post Office
403:. For example, the
277:Signalling System 7
2126:Free-space optical
1693:Frequency-division
1670:Telephone exchange
1540:Charles Wheatstone
1470:Jun-ichi Nishizawa
1445:Innocenzo Manzetti
1380:Reginald Fessenden
1115:Optical telegraphy
948:Telecommunications
610:Service retirement
375:, such as a large
288:quality of service
254:telephone exchange
178:interconnected by
160:fiber-optic cables
2257:
2256:
2090:Answering machine
2006:
2005:
1744:Store and forward
1739:Data transmission
1653:Network switching
1604:Transmission line
1450:Guglielmo Marconi
1415:Internet pioneers
1280:Mohamed M. Atalla
1249:Whistled language
599:regulatory agency
567:V reference point
514:circuit switching
459:two-wire circuits
389:network operators
226:telephone numbers
203:Internet Protocol
180:switching centers
168:cellular networks
132:
131:
124:
106:
16:(Redirected from
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2249:
2248:
2247:
2239:
2238:
2237:
2203:Fax transmission
2151:Submarine cables
2033:
2026:
2019:
2010:
1996:
1995:
1986:
1985:
1976:
1975:
1966:
1965:
1964:
1837:Notable networks
1827:Wireless network
1767:Cellular network
1759:Types of network
1734:Computer network
1621:Network topology
1535:Thomas A. Watson
1390:Oliver Heaviside
1375:Philo Farnsworth
1350:Daniel Davis Jr.
1325:Charles Bourseul
1285:John Logie Baird
994:Data compression
989:Computer network
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529:Digital Signal 1
510:Digital Signal 0
495:routing strategy
449:Digital channels
424:Network topology
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2059:Cable telephony
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1455:Robert Metcalfe
1310:Tim Berners-Lee
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1078:Information Age
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273:multi-frequency
241:to establish a
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224:in the form of
184:central offices
156:telephone lines
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2177:Misdialed call
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1525:Camille Tissot
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1500:Claude Shannon
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1490:Tivadar Puskás
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1460:Antonio Meucci
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1430:Charles K. Kao
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1140:Radiotelephone
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1026:Internet video
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901:(in Icelandic)
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786:(3): 339–355.
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434:Main article:
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401:public utility
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243:telephone call
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148:infrastructure
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2270:Public sphere
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2211:
2209:
2206:
2204:
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2200:
2198:
2194:
2188:
2185:
2183:
2182:Nuisance call
2180:
2178:
2175:
2173:
2170:
2169:
2167:
2163:
2157:
2154:
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2149:
2147:
2144:
2142:
2139:
2137:
2134:
2132:
2129:
2127:
2124:
2122:
2121:Fibre-optical
2119:
2117:
2114:
2112:
2109:
2108:
2106:
2102:
2096:
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2091:
2088:
2087:
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2065:
2062:
2060:
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2051:
2049:
2045:
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2034:
2029:
2027:
2022:
2020:
2015:
2014:
2011:
1999:
1991:
1989:
1981:
1979:
1971:
1969:
1959:
1958:
1955:
1948:
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1929:
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1917:
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1732:
1730:
1727:
1726:
1724:
1720:
1714:
1713:Code-division
1711:
1709:
1706:
1704:
1701:
1699:
1698:Time-division
1696:
1694:
1691:
1689:
1686:
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1683:
1681:
1677:
1671:
1668:
1664:
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1647:
1644:
1643:
1642:
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1634:
1632:
1629:
1628:
1626:
1624:and switching
1622:
1618:
1610:
1607:
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1605:
1602:
1598:
1595:
1594:
1593:
1590:
1588:
1585:
1583:
1580:
1576:
1575:optical fiber
1573:
1572:
1571:
1568:
1566:
1565:Coaxial cable
1563:
1562:
1560:
1558:
1552:
1546:
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1533:
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1528:
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1508:
1506:
1503:
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1498:
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1483:
1481:
1480:Radia Perlman
1478:
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1471:
1468:
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1396:
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1391:
1388:
1386:
1383:
1381:
1378:
1376:
1373:
1371:
1370:Lee de Forest
1368:
1366:
1365:Thomas Edison
1363:
1361:
1358:
1356:
1355:Donald Davies
1353:
1351:
1348:
1346:
1343:
1341:
1340:Claude Chappe
1338:
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1213:
1211:
1208:
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1200:
1197:
1195:
1192:
1190:
1187:
1185:
1184:Smoke signals
1182:
1178:
1175:
1173:
1170:
1168:
1165:
1164:
1163:
1162:Semiconductor
1160:
1156:
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1133:
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1118:
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1100:
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1046:
1042:
1039:
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1034:
1032:
1029:
1027:
1024:
1023:
1022:
1021:Digital media
1019:
1015:
1012:
1010:
1007:
1005:
1002:
1000:
997:
996:
995:
992:
990:
987:
985:
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980:
977:
975:
972:
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967:
965:
962:
961:
959:
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953:
949:
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935:
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928:
923:
922:
919:
900:
896:
890:
887:
875:
871:
865:
863:
859:
847:
843:
837:
834:
821:
817:
813:
812:
807:
806:"TIA TSB-116"
801:
798:
793:
789:
785:
781:
777:
770:
767:
764:
759:
756:
753:
748:
745:
740:
736:
732:
728:
724:
720:
713:
710:
697:
693:
689:
682:
679:
672:
668:
665:
662:
659:
657:
654:
652:
649:
647:
644:
643:
639:
637:
634:
631:
629:
625:
621:
617:
616:SIP telephony
609:
607:
605:
600:
592:
590:
588:
580:
578:
576:
573:areas as the
572:
568:
563:
561:
557:
553:
549:
545:
540:
538:
534:
530:
525:
523:
519:
515:
511:
507:
503:
498:
496:
492:
488:
484:
480:
476:
472:
471:calling party
468:
464:
460:
456:
448:
446:
442:
437:
431:
423:
418:
416:
414:
413:privatization
410:
406:
402:
396:
394:
390:
382:
380:
378:
374:
368:
366:
362:
358:
354:
353:Voice over IP
349:
347:
343:
339:
335:
331:
326:
324:
320:
316:
311:
309:
305:
301:
296:
293:
289:
285:
280:
278:
274:
270:
266:
265:pulse dialing
261:
259:
255:
250:
248:
244:
235:
233:
231:
227:
223:
222:address space
219:
215:
211:
206:
204:
200:
196:
191:
189:
185:
181:
177:
173:
169:
165:
161:
157:
153:
149:
145:
141:
137:
126:
123:
115:
112:December 2021
104:
101:
97:
94:
90:
87:
83:
80:
76:
73: –
72:
68:
67:Find sources:
61:
57:
51:
50:
45:This article
43:
39:
34:
33:
30:
19:
2218:Théâtrophone
2196:Applications
2145:
2104:Connectivity
2064:Mobile phone
1796:
1680:Multiplexing
1555:Transmission
1520:Nikola Tesla
1510:Henry Sutton
1465:Samuel Morse
1395:Robert Hooke
1360:Amos Dolbear
1295:John Bardeen
1214:
1194:Telautograph
1098:Mobile phone
1053:Edholm's law
1036:social media
969:Broadcasting
903:. Retrieved
898:
889:
877:. Retrieved
873:
849:. Retrieved
845:
836:
824:. Retrieved
809:
800:
783:
779:
769:
758:
747:
722:
712:
700:. Retrieved
681:
667:Via Net Loss
635:
632:
613:
596:
584:
575:V5 interface
564:
562:technology.
541:
526:
499:
475:called party
452:
443:
439:
397:
386:
369:
361:cable modems
350:
346:cable modems
327:
312:
297:
292:A. K. Erlang
281:
262:
251:
239:
207:
199:core network
192:
139:
135:
133:
118:
109:
99:
92:
85:
78:
66:
54:Please help
49:verification
46:
29:
2223:Video calls
2172:Missed call
2083:Accessories
1880:NPL network
1592:Radio waves
1530:Alfred Vail
1440:Hedy Lamarr
1425:Dawon Kahng
1385:Elisha Gray
1345:Yogen Dalal
1270:Nasir Ahmed
1204:Teleprinter
1068:Heliographs
874:BT Business
846:www.yay.com
826:20 November
548:synchronous
479:sample rate
214:Bell System
2264:Categories
2074:Photophone
1926:Antarctica
1885:Toasternet
1807:Television
1290:Paul Baran
1222:Television
1206:(teletype)
1199:Telegraphy
1177:transistor
1155:Phryctoria
1125:Photophone
1103:Smartphone
1093:Mass media
811:IHS Markit
673:References
593:Regulation
467:local loop
428:See also:
419:Technology
186:, network
182:, such as
82:newspapers
2280:Telephony
2187:Phone tag
2095:Caller ID
2040:Telephony
1910:Americas
1899:Locations
1870:Internet2
1631:Bandwidth
1335:Vint Cerf
1232:streaming
1210:Telephone
1150:Semaphore
1041:streaming
879:4 October
851:4 October
739:1556-5068
656:Phreaking
537:E-carrier
533:T-carrier
506:Bell Labs
485:known as
463:last mile
383:Operators
330:last mile
247:signaling
152:telephony
144:telephony
2054:Landline
1978:Category
1865:Internet
1855:CYCLADES
1772:Ethernet
1722:Concepts
1646:terminal
1597:wireless
1420:Bob Kahn
1263:Pioneers
1088:Internet
979:Cable TV
905:29 April
899:MĂla ehf
820:Archived
696:Archived
692:HuffPost
640:See also
518:timeslot
373:gateways
323:Internet
1998:Commons
1988:Outline
1941:Oceania
1860:FidoNet
1845:ARPANET
1658:circuit
1227:digital
956:History
379:(PBX).
321:of the
236:History
188:tandems
166:links,
96:scholar
1936:Europe
1906:Africa
1890:Usenet
1850:BITNET
1787:Mobile
1663:packet
1172:MOSFET
1167:device
964:Beacon
737:
702:4 July
663:(POTS)
502:kbit/s
455:trunks
344:, and
258:trunks
195:analog
174:, and
98:
91:
84:
77:
69:
2165:Calls
2047:Types
1919:South
1914:North
1875:JANET
1812:Telex
1802:Radio
1641:Nodes
1636:Links
1557:media
1135:Radio
1120:Pager
1048:Drums
1014:video
1009:image
999:audio
628:E.164
624:E.163
552:SONET
487:G.711
473:to a
218:E.164
210:ITU-T
103:JSTOR
89:books
2156:VoIP
2146:PSTN
2141:POTS
2131:ISDN
1931:Asia
1817:UUCP
1777:ISDN
907:2024
881:2023
853:2023
828:2011
735:ISSN
704:2020
626:and
571:ETSI
554:and
491:ISUP
342:FTTx
338:ISDN
304:X.25
140:PSTN
134:The
75:news
1822:WAN
1792:NGN
1782:LAN
1063:Fax
1004:DCT
788:doi
727:doi
560:PDH
363:or
357:DSL
334:DSL
58:by
2266::
897:.
872:.
861:^
844:.
818:.
814:.
808:.
784:14
782:.
778:.
733:.
725:.
721:.
694:.
690:.
606:.
577:.
527:A
497:.
415:.
359:,
340:,
336:,
325:.
249:.
170:,
162:,
158:,
2032:e
2025:t
2018:v
1949:)
1945:(
940:e
933:t
926:v
909:.
883:.
855:.
830:.
794:.
790::
741:.
729::
706:.
138:(
125:)
119:(
114:)
110:(
100:·
93:·
86:·
79:·
52:.
20:)
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