235:
stations had as few as one or two channels. Each telephone conversation (connection) required the exclusive use of a channel for the duration. Because of this limitation these systems had a much lower capacity than cellular systems and all channels busy conditions were common. In larger cities this dictated a very limited number of simultaneous calls. Each subscriber was given a packet of dialing and use instructions. Roaming (receiving calls out of the "home area") was achieved by selecting the specific channels used by the tower and service provider the user was traveling in and dialing a three-digit code, thereby logging the user's land number at that location. This process had to be repeated at each tower which, as noted, usually had a range of 40–60 miles. Some areas only had half-duplex (one-way) communications and required the push-to-talk switch in the handset, between the mouthpiece and the earpiece. Two lights on the "head" indicated busy (red) if no channels were idle and in-use (green) if connected to the tower, or depressing the push-to-talk switch. There was no encryption and all conversations were public.
193:
a "head unit" or the telephone handset which sat in a cradle with a direct dialing keyboard. These looked and functioned much like a landline, or hardwired, telephone. Unlike cellular handsets, these units passed through a dial tone when the receiver was lifted from the cradle and in this way seemed more like a landline telephone. There was a separate large radio transceiver chassis, typically measuring at least a foot square and 6 inches high, mounted either in the trunk or under the seats of an automobile. These transceivers were connected to the handset cradle with a multi-conductor cable usually around .5 inch thick.
1806:
184:
dialing but with the addition of rudimentary parity checking. Digits are formed with a pulsetrain of alternating tones, either connect and silence (for odd digits) or connect and guard (for even digits). When the base station received the calling party's identification, it would send dialtone to the mobile. The user would then use the rotary dial, which would send the dialed digits as an alternating 10 pps pulse train (originally, directly formed by the rotary dial) of connect and guard tones.
175:
logic was performed with discrete transistors. In a given city, one IMTS base station channel was "marked idle" by the transmission of a steady 2000 Hz "idle" tone. Mobiles would scan the available frequencies and lock on to the channel transmitting the idle tone. When a call was placed to a mobile, the idle tone would change to 1800 Hz "channel seize" tone (the idle tone would appear on another frequency, if available), and the 7 digit mobile number (three digits of the
31:
180:
then transmit 2150 Hz "guard" tone back to the base station. This would also initiate ringing at the mobile, and when the mobile subscriber picked up the phone, 1633 Hz "connect" tone would be sent back to the base station to indicate answer supervision and the voice path would be cut through. When the mobile hung up, a burst of alternating 1336 "disconnect" and 1800 Hz "seize" tones would be sent to allow the base station to service another call.
2877:
743:
Availability of the channels was scarce hence airtime was also quite expensive at $ 0.70-1.20 per minute. Following the divestiture, customer-owned equipment was required by Bell companies and monthly rates then typically ran to $ 25 plus air time. Also, since there were so few channels, it was common for the phones to "queue up" to use a channel and IMTS manufacturers competed for the speed with which the units would seize an available channel.
686:
94:
2887:
2866:
1795:
2897:
217:, allowing only one party to transmit at a time; the user had to "push to talk" to speak and then "unkey" the transmitter to hear the other party on the line. In 1960 General Electric introduced the "Progress Line" DTO- series MTS mobiles which were full duplex, although subscribers were still required to press the "push to talk" bar on the handset to speak.
158:" on a secondary basis on the same channels, but soon, with the growth of paging, RCC mobile phone services were given lower priority. Some RCCs utilized IMTS technology, but most adopted the "Secode-2805" system which allowed for simultaneous paging, so after a few years, the predominant provider of mobile telephone service was the Bell System companies.
192:
IMTS systems typically had 25 watts of transmitter power at the mobile station and 100-250 Watts at the terminal — unlike the newer cellular car telephones that had maximum power output of 3 watts and modern cellular handsets with power outputs of 0.6 watts. Mobile installations normally consisted of
183:
Mobiles would originate calls by sending a burst of connect tone, to which the base station responded with a burst of seize tone. The mobile would then respond with its identification, consisting of its area code and last four digits of the phone number sent at 20 pulses per second, just as in inward
170:
remedied this problem by decreasing the area covered by one tower (a "cell") and increasing the number of cells. The disadvantage of this is more towers are required to cover a given area. Thus, IMTS and MTS systems still exist in some remote areas, as it may be the only feasible way to cover a large
746:
The limit of customer numbers on MTS and IMTS was the driver for investment in cellular networks. In remote regions, this is not the case; in remote regions, obsolescence is the driver, but the lack of a suitable and affordable alternative has resulted in regulatory obstacles: customers did not want
225:
the terminal into believing an IMTS mobile was using the system. These units were not very common or practical because they lacked the power to reliably connect to the base station over the distances common in the IMTS systems. A compromise existed with the briefcase phone, which had somewhat higher
179:
and the last four digits of subscriber number, the NXX was not sent) would be sent out as rotary dial pulses, switching between 2000 and 1800 Hz to represent digits. Any mobile recognizing that the call was for someone else would resume scanning for mark idle tone, while the called mobile would
234:
IMTS base station sites generally covered an area 40–60 miles in diameter. This extended range was due to both their large transmitter power and in many cases higher antenna placement at anywhere from 100 to 500 ft. IMTS base stations in larger cities had as many as 7 or 8 channels while rural
205:
and were about 19 in. long (1/4 wavelength at 155 MHz). These mobile telephone systems required a large amount of power (10 to 15 amperes at 12 volts) and this was supplied by thick power cabling connected directly to the automobile's battery. It therefore was quite possible and not uncommon
146:
The original Bell System US and
Canadian mobile telephone system includes three frequency bands, VHF Low (35-44 MHz, 9 channels), VHF High (152-158 MHz, 11 channels in the U.S., 13 channels in Canada), and UHF (454-460 MHz, 12 channels). Alternative names were "Low Band", "High band"
174:
The basic operation of IMTS was very advanced for its time, considering that integrated circuits were not commonly available. The most common IMTS phone, the
Motorola TLD-1100 series, used two circuit boards about 8 inches square, to perform the channel scanning and digit decoding process, and all
247:
and the
Improved Mobile Telephone Service. The low band "Z" prefixed channels were always operated in the MTS, or manual mode. The "Z" channels were sold at auction by the FCC in approximately 2003 to other services and remain largely unused. The VHF and UHF frequencies have been opened to other
206:
for an IMTS telephone to drain an automobile's battery if used for moderate periods of time without the automobile engine running or if left on overnight. Optionally these units were also connected to the car's horn and could honk the horn as a ringer to summon a user who was away from the car.
738:
IMTS technology severely limited the total number of subscribers. In the 1970s and the early 1980s, before the introduction of cellular phones, there were "waiting lists" of up to three years for those wishing to have mobile telephone service. These potential subscribers were waiting for other
742:
These limitations resulted in low quantity sales and production of IMTS phones and the mobile units were therefore very expensive ($ 2,000 to $ 4,000). Prior to the divestiture of AT&T in 1984, Bell System IMTS subscribers usually leased the equipment at a monthly rate of up to $ 120.
220:
There were also IMTS handheld transceivers (Yaesu's 1982 vintage
Traveler) that operated on 2-4 watts, and these were all half duplex. These were essentially modified "walkie-talkies" with a DTMF (dual tone multi-frequency) keypad attached on the front panel, which
161:
A given provider might have offered service on one, two, or all three bands, although IMTS was never offered on low band (only MTS, but
Whidbey Telephone in Washington State had a custom-designed direct-dial system.) These were prone to network congestion and
196:
The mobile antennas almost always required a hole to be drilled in the body of the car to mount the antenna in; until the 1970s there were no "on-glass" antennas - these were developed later for the cellular car-mounted telephones. These
226:
power in the range of 10 to 20 watts (depending on how much battery was in the briefcase), and which was full duplex. Typical IMTS briefcase phones were made by Canyon, GCS, SCM Melabs and
Livermore Data Systems.
151:) channels, another 7 channels at VHF, and 12 channels at UHF were granted to non-wireline companies designated as "RCCs" (Radio Common Carriers). These RCC channels were adjacent to the Bell System frequencies.
747:
the MTS/IMTS service to be withdrawn. Increasing affordability of satellite service, and government investment in cellular expansion allowed MTS and IMTS to be removed.
923:
2141:
859:
213:, meaning that a user could both talk and hear the other party at the same time. This was an improvement over the earlier MTS systems, most of which were
703:
111:
1401:
2921:
1422:
1769:
1649:
2849:
2821:
2816:
1841:
1661:
1221:
803:
948:
1599:
1573:
852:
251:
The two VHF high-band channels designated JJ and JW were used only in Canada, and were not available for use in the United States.
2843:
1729:
2926:
2838:
2828:
2808:
2610:
1178:
1634:
1075:
1975:
2900:
2833:
2679:
1266:
845:
2605:
1644:
2699:
1333:
982:
725:
133:
77:
61:
739:
subscribers to disconnect their subscription in order to obtain a mobile telephone number and mobile phone service.
76:(MTS) and improved on most MTS systems by offering direct-dial rather than connections through a live operator, and
2484:
2032:
1834:
1345:
928:
878:
17:
2595:
1734:
1338:
908:
2590:
1680:
707:
115:
2615:
1673:
1656:
176:
2890:
2651:
2548:
2091:
1886:
1858:
1173:
1119:
1094:
977:
968:
756:
166:
since a radio closer to the terminal would sometimes take over the channel because of its stronger signal.
1687:
2880:
2387:
1827:
1134:
2739:
2661:
2600:
2307:
2511:
2472:
2317:
2217:
2146:
2079:
1906:
1129:
775:, the earliest 'car telephone' service provided by the Bell System, later replaced by IMTS technology
2870:
2112:
2047:
2000:
1960:
1799:
1629:
1391:
1385:
1379:
1328:
1296:
898:
772:
244:
73:
2709:
2694:
2538:
2489:
2412:
2312:
1990:
1876:
1871:
1749:
1357:
998:
696:
163:
104:
807:
2631:
2417:
2232:
2177:
2172:
1985:
1950:
1774:
886:
767:
2533:
2337:
2302:
2222:
2202:
2124:
2012:
1933:
1712:
1639:
1065:
1866:
2447:
2407:
2377:
2134:
2069:
1891:
1717:
1702:
1692:
918:
913:
54:
8:
2457:
2397:
2156:
2118:
1916:
1901:
1707:
1697:
50:
2684:
2641:
2572:
2442:
2372:
2347:
2282:
2129:
1850:
243:
The frequencies listed below (in MHz) are those formerly used in the US & Canadian
148:
2724:
2646:
2560:
2543:
2506:
2352:
2182:
2151:
2017:
1911:
1810:
2392:
2729:
2689:
2669:
2636:
2565:
2523:
2437:
2292:
2277:
2252:
2227:
2187:
2037:
1896:
1881:
1724:
1624:
1619:
1496:
938:
868:
167:
47:
2357:
2212:
1980:
1955:
1943:
1668:
2555:
2427:
2402:
2362:
2332:
2207:
2042:
1995:
1970:
1928:
1759:
1754:
1583:
1200:
889:
778:
65:
2915:
2704:
2477:
2467:
2382:
2272:
2267:
2257:
2242:
2064:
1923:
1764:
837:
783:
2582:
2422:
2367:
2297:
2262:
2197:
2096:
2086:
1938:
1739:
1486:
1470:
1103:
198:
30:
2782:
2432:
2342:
2327:
2287:
2247:
2106:
1568:
1517:
1427:
1415:
2787:
2494:
2192:
2101:
2057:
2027:
2005:
710: in this section. Unsourced material may be challenged and removed.
118: in this section. Unsourced material may be challenged and removed.
1194:
2772:
2237:
2052:
1819:
762:
685:
93:
2767:
2757:
2674:
2499:
2322:
1547:
1451:
1350:
1273:
1240:
202:
69:
2762:
2747:
1965:
1781:
1311:
1278:
1153:
1084:
1018:
1013:
933:
831:
154:
RCCs were also allowed to offer paging services to "beepers" or "
2792:
2752:
2074:
1490:
1361:
1261:
1003:
943:
248:
services unrelated to mobile telephony and largely reassigned.
155:
2777:
2714:
2022:
1578:
1563:
1526:
1513:
1432:
1410:
1216:
1008:
57:
2719:
1744:
1442:
1256:
1124:
1051:
1164:
1139:
1060:
1047:
1023:
1542:
1465:
1235:
1037:
958:
80:
operation so both parties could talk at the same time.
72:
dial phone service. Introduced in 1964, it replaced
2913:
867:
1835:
853:
2850:Global telecommunications regulation bodies
147:and "UHF". In addition to the Bell system (
2886:
1842:
1828:
860:
846:
726:Learn how and when to remove this message
134:Learn how and when to remove this message
83:
29:
2922:Telecommunications in the United States
14:
2914:
1849:
1730:Multimedia Broadcast Multicast Service
1823:
841:
2896:
1688:Spectral efficiency comparison table
708:adding citations to reliable sources
679:
116:adding citations to reliable sources
87:
24:
25:
2938:
825:
40:Improved Mobile Telephone Service
34:IMTS mobile phone in a briefcase.
2895:
2885:
2876:
2875:
2864:
2485:Free-space optical communication
1804:
1793:
879:List of mobile phone generations
684:
201:looked much like those used for
92:
695:needs additional citations for
229:
103:needs additional citations for
27:Early mobile telephone standard
796:
675:
238:
13:
1:
804:"2005 CFR Title 47, Volume 2"
789:
2927:Telecommunications in Canada
2871:Telecommunication portal
2652:Telecommunications equipment
1800:Telecommunication portal
757:Advanced Mobile Phone System
7:
2388:Alexander Stepanovich Popov
750:
253:
187:
60:system which linked to the
10:
2943:
2092:Telecommunications history
1297:CDMA2000 1xEV-DO Release 0
834:- overview of MTS and IMTS
2859:
2801:
2738:
2700:Public Switched Telephone
2660:
2624:
2581:
2522:
2512:telecommunication circuit
2473:Fiber-optic communication
2456:
2218:Francis Blake (telephone)
2165:
2013:Optical telecommunication
1857:
1790:
1612:
1592:
1556:
1541:
1506:
1479:
1464:
1441:
1400:
1371:
1321:
1310:
1289:
1249:
1234:
1209:
1187:
1179:EDGE/EGPRS - Evolved EDGE
1163:
1152:
1112:
1104:D-AMPS (IS-54 and IS-136)
1093:
1074:
1046:
1036:
991:
967:
957:
885:
876:
534:
384:
267:
171:sparsely-populated area.
2611:Orbital angular-momentum
2048:Satellite communications
1887:Communications satellite
773:Mobile Telephone Service
245:Mobile Telephone Service
74:Mobile Telephone Service
62:public telephone network
2490:Molecular communication
2313:Gardiner Greene Hubbard
2142:Undersea telegraph line
1877:Cable protection system
1635:Comparison of standards
1274:UTRA-TDD LCR / TD-SCDMA
2632:Communication protocol
2418:Charles Sumner Tainter
2233:Walter Houser Brattain
2178:Edwin Howard Armstrong
1986:Information revolution
1640:Channel access methods
1279:UTRA-TDD HCR / TD-CDMA
768:Mobile radio telephone
35:
2606:Polarization-division
2338:Narinder Singh Kapany
2303:Erna Schneider Hoover
2223:Jagadish Chandra Bose
2203:Alexander Graham Bell
1934:online video platform
1811:Telephones portal
919:MTA - MTB - MTC - MTD
84:Technical Information
33:
2448:Vladimir K. Zworykin
2408:Almon Brown Strowger
2378:Charles Grafton Page
2033:Prepaid mobile phone
1961:Electrical telegraph
1428:iBurst (IEEE 802.20)
1201:CDMA2000 1X Advanced
832:THE MOBILE TELEPHONE
704:improve this article
209:The IMTS units were
112:improve this article
2398:Johann Philipp Reis
2157:Wireless revolution
2119:The Telephone Cases
1976:Hydraulic telegraph
1314:(3.5G, 3.75G, 3.9G)
1156:(2.5G, 2.75G, 2.9G)
924:Mobile TeleSeratout
2596:Frequency-division
2573:Telephone exchange
2443:Charles Wheatstone
2373:Jun-ichi Nishizawa
2348:Innocenzo Manzetti
2283:Reginald Fessenden
2018:Optical telegraphy
1851:Telecommunications
1802:
1388:(TIA/EIA/IS-856-B)
1382:(TIA/EIA/IS-856-A)
1380:1xEV-DO Revision A
149:wireline incumbent
36:
2909:
2908:
2647:Store and forward
2642:Data transmission
2556:Network switching
2507:Transmission line
2353:Guglielmo Marconi
2318:Internet pioneers
2183:Mohamed M. Atalla
2152:Whistled language
1817:
1816:
1620:Cellular networks
1608:
1607:
1537:
1536:
1460:
1459:
1306:
1305:
1262:UTRA-FDD / W-CDMA
1230:
1229:
1197:(TIA/EIA/IS-2000)
1148:
1147:
1032:
1031:
736:
735:
728:
673:
672:
263:Mobile frequency
168:Cellular networks
144:
143:
136:
16:(Redirected from
2934:
2899:
2898:
2889:
2888:
2879:
2878:
2869:
2868:
2867:
2740:Notable networks
2730:Wireless network
2670:Cellular network
2662:Types of network
2637:Computer network
2524:Network topology
2438:Thomas A. Watson
2293:Oliver Heaviside
2278:Philo Farnsworth
2253:Daniel Davis Jr.
2228:Charles Bourseul
2188:John Logie Baird
1897:Data compression
1892:Computer network
1844:
1837:
1830:
1821:
1820:
1809:
1808:
1807:
1798:
1797:
1796:
1725:Mobile broadband
1625:Mobile telephony
1613:Related articles
1554:
1553:
1497:LTE Advanced Pro
1477:
1476:
1392:EV-DO Revision C
1386:EV-DO Revision B
1319:
1318:
1247:
1246:
1161:
1160:
1044:
1043:
965:
964:
890:radio telephones
869:Cellular network
862:
855:
848:
839:
838:
819:
818:
816:
815:
806:. Archived from
800:
731:
724:
720:
717:
711:
688:
680:
254:
139:
132:
128:
125:
119:
96:
88:
64:. IMTS was the
21:
18:IMTS frequencies
2942:
2941:
2937:
2936:
2935:
2933:
2932:
2931:
2912:
2911:
2910:
2905:
2865:
2863:
2855:
2797:
2734:
2656:
2620:
2577:
2526:
2518:
2459:
2452:
2358:Robert Metcalfe
2213:Tim Berners-Lee
2161:
1981:Information Age
1853:
1848:
1818:
1813:
1805:
1803:
1794:
1792:
1786:
1693:Frequency bands
1604:
1588:
1546:
1533:
1502:
1469:
1456:
1437:
1396:
1367:
1313:
1312:3G transitional
1302:
1285:
1239:
1226:
1205:
1183:
1155:
1154:2G transitional
1144:
1108:
1089:
1085:cdmaOne (IS-95)
1070:
1028:
987:
953:
881:
872:
866:
828:
823:
822:
813:
811:
802:
801:
797:
792:
753:
732:
721:
715:
712:
701:
689:
678:
241:
232:
190:
140:
129:
123:
120:
109:
97:
86:
28:
23:
22:
15:
12:
11:
5:
2940:
2930:
2929:
2924:
2907:
2906:
2904:
2903:
2893:
2883:
2873:
2860:
2857:
2856:
2854:
2853:
2846:
2841:
2836:
2831:
2826:
2825:
2824:
2819:
2811:
2805:
2803:
2799:
2798:
2796:
2795:
2790:
2785:
2780:
2775:
2770:
2765:
2760:
2755:
2750:
2744:
2742:
2736:
2735:
2733:
2732:
2727:
2722:
2717:
2712:
2707:
2702:
2697:
2692:
2687:
2682:
2677:
2672:
2666:
2664:
2658:
2657:
2655:
2654:
2649:
2644:
2639:
2634:
2628:
2626:
2622:
2621:
2619:
2618:
2613:
2608:
2603:
2598:
2593:
2591:Space-division
2587:
2585:
2579:
2578:
2576:
2575:
2570:
2569:
2568:
2563:
2553:
2552:
2551:
2541:
2536:
2530:
2528:
2520:
2519:
2517:
2516:
2515:
2514:
2504:
2503:
2502:
2492:
2487:
2482:
2481:
2480:
2470:
2464:
2462:
2454:
2453:
2451:
2450:
2445:
2440:
2435:
2430:
2428:Camille Tissot
2425:
2420:
2415:
2410:
2405:
2403:Claude Shannon
2400:
2395:
2393:Tivadar Puskás
2390:
2385:
2380:
2375:
2370:
2365:
2363:Antonio Meucci
2360:
2355:
2350:
2345:
2340:
2335:
2333:Charles K. Kao
2330:
2325:
2320:
2315:
2310:
2308:Harold Hopkins
2305:
2300:
2295:
2290:
2285:
2280:
2275:
2270:
2265:
2260:
2255:
2250:
2245:
2240:
2235:
2230:
2225:
2220:
2215:
2210:
2208:Emile Berliner
2205:
2200:
2195:
2190:
2185:
2180:
2175:
2169:
2167:
2163:
2162:
2160:
2159:
2154:
2149:
2147:Videotelephony
2144:
2139:
2138:
2137:
2132:
2122:
2115:
2110:
2104:
2099:
2094:
2089:
2084:
2083:
2082:
2077:
2072:
2062:
2061:
2060:
2050:
2045:
2043:Radiotelephone
2040:
2035:
2030:
2025:
2020:
2015:
2010:
2009:
2008:
1998:
1993:
1988:
1983:
1978:
1973:
1968:
1963:
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1953:
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1929:Internet video
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1011:
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986:
985:
980:
974:
972:
962:
955:
954:
952:
951:
946:
941:
936:
934:Autotel (PALM)
931:
926:
921:
916:
911:
906:
901:
895:
893:
883:
882:
877:
874:
873:
865:
864:
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850:
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836:
835:
827:
826:External links
824:
821:
820:
794:
793:
791:
788:
787:
786:
781:
779:Radiotelephone
776:
770:
765:
760:
752:
749:
734:
733:
692:
690:
683:
677:
674:
671:
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298:
294:
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287:
283:
282:
279:
276:
272:
271:
265:
264:
261:
260:Base frequency
258:
240:
237:
231:
228:
189:
186:
142:
141:
100:
98:
91:
85:
82:
68:equivalent of
66:radiotelephone
26:
9:
6:
4:
3:
2:
2939:
2928:
2925:
2923:
2920:
2919:
2917:
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2678:
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2648:
2645:
2643:
2640:
2638:
2635:
2633:
2630:
2629:
2627:
2623:
2617:
2616:Code-division
2614:
2612:
2609:
2607:
2604:
2602:
2601:Time-division
2599:
2597:
2594:
2592:
2589:
2588:
2586:
2584:
2580:
2574:
2571:
2567:
2564:
2562:
2559:
2558:
2557:
2554:
2550:
2547:
2546:
2545:
2542:
2540:
2537:
2535:
2532:
2531:
2529:
2527:and switching
2525:
2521:
2513:
2510:
2509:
2508:
2505:
2501:
2498:
2497:
2496:
2493:
2491:
2488:
2486:
2483:
2479:
2478:optical fiber
2476:
2475:
2474:
2471:
2469:
2468:Coaxial cable
2466:
2465:
2463:
2461:
2455:
2449:
2446:
2444:
2441:
2439:
2436:
2434:
2431:
2429:
2426:
2424:
2421:
2419:
2416:
2414:
2411:
2409:
2406:
2404:
2401:
2399:
2396:
2394:
2391:
2389:
2386:
2384:
2383:Radia Perlman
2381:
2379:
2376:
2374:
2371:
2369:
2366:
2364:
2361:
2359:
2356:
2354:
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2336:
2334:
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2329:
2326:
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2309:
2306:
2304:
2301:
2299:
2296:
2294:
2291:
2289:
2286:
2284:
2281:
2279:
2276:
2274:
2273:Lee de Forest
2271:
2269:
2268:Thomas Edison
2266:
2264:
2261:
2259:
2258:Donald Davies
2256:
2254:
2251:
2249:
2246:
2244:
2243:Claude Chappe
2241:
2239:
2236:
2234:
2231:
2229:
2226:
2224:
2221:
2219:
2216:
2214:
2211:
2209:
2206:
2204:
2201:
2199:
2196:
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2191:
2189:
2186:
2184:
2181:
2179:
2176:
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2171:
2170:
2168:
2164:
2158:
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2140:
2136:
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2116:
2114:
2111:
2108:
2105:
2103:
2100:
2098:
2095:
2093:
2090:
2088:
2087:Smoke signals
2085:
2081:
2078:
2076:
2073:
2071:
2068:
2067:
2066:
2065:Semiconductor
2063:
2059:
2056:
2055:
2054:
2051:
2049:
2046:
2044:
2041:
2039:
2036:
2034:
2031:
2029:
2026:
2024:
2021:
2019:
2016:
2014:
2011:
2007:
2004:
2003:
2002:
1999:
1997:
1994:
1992:
1989:
1987:
1984:
1982:
1979:
1977:
1974:
1972:
1969:
1967:
1964:
1962:
1959:
1957:
1954:
1952:
1949:
1945:
1942:
1940:
1937:
1935:
1932:
1930:
1927:
1926:
1925:
1924:Digital media
1922:
1918:
1915:
1913:
1910:
1908:
1905:
1903:
1900:
1899:
1898:
1895:
1893:
1890:
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1883:
1880:
1878:
1875:
1873:
1870:
1868:
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1838:
1833:
1831:
1826:
1825:
1822:
1812:
1801:
1789:
1783:
1780:
1776:
1775:Wi-Fi Calling
1773:
1771:
1768:
1766:
1763:
1761:
1758:
1756:
1753:
1752:
1751:
1748:
1746:
1743:
1741:
1738:
1736:
1735:NGMN Alliance
1733:
1731:
1728:
1726:
1723:
1719:
1716:
1714:
1711:
1709:
1706:
1704:
1701:
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1671:
1670:
1667:
1663:
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1633:
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1621:
1618:
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1615:
1611:
1601:
1598:
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1582:
1580:
1577:
1575:
1572:
1570:
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1565:
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1528:
1525:
1522:
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1509:
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1498:
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1492:
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1484:
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1478:
1475:
1472:
1467:
1463:
1453:
1450:
1449:
1447:
1444:
1440:
1434:
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1426:
1424:
1421:
1417:
1414:
1413:
1412:
1409:
1408:
1406:
1403:
1399:
1393:
1390:
1387:
1384:
1381:
1377:
1376:
1374:
1370:
1363:
1359:
1356:
1352:
1349:
1348:
1347:
1344:
1340:
1337:
1335:
1332:
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1330:
1327:
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1324:
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1317:
1315:
1309:
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1260:
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1258:
1255:
1254:
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1248:
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1237:
1233:
1223:
1220:
1218:
1215:
1214:
1212:
1208:
1202:
1199:
1196:
1193:
1192:
1190:
1186:
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1177:
1175:
1172:
1171:
1169:
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1162:
1159:
1157:
1151:
1141:
1138:
1136:
1133:
1131:
1128:
1126:
1123:
1121:
1118:
1117:
1115:
1111:
1105:
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1101:
1099:
1096:
1092:
1086:
1083:
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1080:
1077:
1073:
1067:
1064:
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1042:
1039:
1035:
1025:
1022:
1020:
1017:
1015:
1012:
1010:
1007:
1005:
1002:
1000:
997:
996:
994:
990:
984:
981:
979:
978:AMPS - N-AMPS
976:
975:
973:
970:
966:
963:
960:
956:
950:
947:
945:
942:
940:
937:
935:
932:
930:
927:
925:
922:
920:
917:
915:
912:
910:
907:
905:
902:
900:
897:
896:
894:
891:
888:
884:
880:
875:
870:
863:
858:
856:
851:
849:
844:
843:
840:
833:
830:
829:
810:on 2008-02-07
809:
805:
799:
795:
785:
784:Two-way radio
782:
780:
777:
774:
771:
769:
766:
764:
761:
758:
755:
754:
748:
744:
740:
730:
727:
719:
709:
705:
699:
698:
693:This section
691:
687:
682:
681:
668:
665:
662:
661:
657:
654:
651:
650:
646:
643:
640:
639:
635:
632:
629:
628:
624:
621:
618:
617:
613:
610:
607:
606:
602:
599:
596:
595:
591:
588:
585:
584:
580:
577:
574:
573:
569:
566:
563:
562:
558:
555:
552:
551:
547:
544:
541:
540:
537:
533:
529:
526:
523:
522:
518:
515:
512:
511:
507:
504:
501:
500:
496:
493:
490:
489:
485:
482:
479:
478:
474:
471:
468:
467:
463:
460:
457:
456:
452:
449:
446:
445:
441:
438:
435:
434:
430:
427:
424:
423:
419:
416:
413:
412:
408:
405:
402:
401:
397:
394:
391:
390:
387:
386:VHF High Band
383:
379:
376:
373:
372:
368:
365:
362:
361:
357:
354:
351:
350:
346:
343:
340:
339:
335:
332:
329:
328:
324:
321:
318:
317:
313:
310:
307:
306:
302:
299:
296:
295:
291:
288:
285:
284:
280:
277:
274:
273:
270:
266:
262:
259:
256:
255:
252:
249:
246:
236:
227:
224:
218:
216:
212:
207:
204:
200:
199:whip antennas
194:
185:
181:
178:
172:
169:
165:
159:
157:
152:
150:
138:
135:
127:
117:
113:
107:
106:
101:This section
99:
95:
90:
89:
81:
79:
75:
71:
67:
63:
59:
56:
52:
49:
45:
41:
32:
19:
2583:Multiplexing
2458:Transmission
2423:Nikola Tesla
2413:Henry Sutton
2368:Samuel Morse
2298:Robert Hooke
2263:Amos Dolbear
2198:John Bardeen
2117:
2097:Telautograph
2001:Mobile phone
1956:Edholm's law
1939:social media
1872:Broadcasting
1740:Push-to-talk
1518:IEEE 802.16m
1487:LTE Advanced
1471:IMT Advanced
1416:IEEE 802.16e
1411:Mobile WiMAX
1372:3GPP2 family
1299:(TIA/IS-856)
1290:3GPP2 family
1188:3GPP2 family
1167:/3GPP family
983:TACS - ETACS
903:
812:. Retrieved
808:the original
798:
745:
741:
737:
722:
713:
702:Please help
697:verification
694:
535:
385:
269:VHF Low Band
268:
250:
242:
233:
230:Base station
222:
219:
214:
210:
208:
195:
191:
182:
173:
164:interference
160:
153:
145:
130:
121:
110:Please help
105:verification
102:
46:) was a pre-
43:
39:
37:
2783:NPL network
2495:Radio waves
2433:Alfred Vail
2343:Hedy Lamarr
2328:Dawon Kahng
2288:Elisha Gray
2248:Yogen Dalal
2173:Nasir Ahmed
2107:Teleprinter
1971:Heliographs
1569:5G-Advanced
1557:3GPP family
1507:IEEE family
1499:(4.5G/4.9G)
1480:3GPP family
1322:3GPP family
1250:3GPP family
1195:CDMA2000 1X
1066:CSD - HSCSD
759:, successor
676:Limitations
239:Frequencies
215:half duplex
211:full duplex
78:full-duplex
2916:Categories
2829:Antarctica
2788:Toasternet
2710:Television
2193:Paul Baran
2125:Television
2109:(teletype)
2102:Telegraphy
2080:transistor
2058:Phryctoria
2028:Photophone
2006:Smartphone
1996:Mass media
1423:Flash-OFDM
814:2009-10-16
790:References
716:April 2016
124:April 2016
2813:Americas
2802:Locations
2773:Internet2
2534:Bandwidth
2238:Vint Cerf
2135:streaming
2113:Telephone
2053:Semaphore
1944:streaming
1523:WiMax 2.1
1378:CDMA2000
871:standards
763:Car phone
203:CB radios
2881:Category
2768:Internet
2758:CYCLADES
2675:Ethernet
2625:Concepts
2549:terminal
2500:wireless
2323:Bob Kahn
2166:Pioneers
1991:Internet
1882:Cable TV
1548:IMT-2020
1452:HiperMAN
1351:DC-HSDPA
1241:IMT-2000
751:See also
669:459.650
658:459.625
647:459.600
636:459.575
625:459.550
614:459.525
603:459.500
592:459.475
581:459.450
570:459.425
559:459.400
548:459.375
536:UHF Band
188:Terminal
48:cellular
2901:Commons
2891:Outline
2844:Oceania
2763:FidoNet
2748:ARPANET
2561:circuit
2130:digital
1859:History
1782:Osmocom
1630:History
1600:DECT-5G
1574:NR-IIoT
1019:DataTAC
1014:Mobitex
666:454.650
655:454.625
644:454.600
633:454.575
622:454.550
611:454.525
600:454.500
589:454.475
578:454.450
567:454.425
556:454.400
545:454.375
530:158.10
519:158.07
508:158.04
497:158.01
486:157.98
475:157.95
464:157.92
453:157.89
442:157.86
431:157.83
420:157.80
409:157.77
398:157.74
257:Channel
2839:Europe
2809:Africa
2793:Usenet
2753:BITNET
2690:Mobile
2566:packet
2075:MOSFET
2070:device
1867:Beacon
1584:NB-IoT
1550:(2021)
1545:(2018)
1491:E-UTRA
1473:(2013)
1468:(2009)
1445:family
1404:family
1362:E-UTRA
1243:(2001)
1238:(1998)
1097:family
1078:family
1054:family
1040:(1991)
971:family
961:(1979)
944:B-Netz
892:(1946)
527:152.84
516:152.81
505:152.78
494:152.75
483:152.72
472:152.69
461:152.66
450:152.63
439:152.60
428:152.57
417:152.54
406:152.51
395:152.48
380:43.66
369:43.62
358:43.54
347:43.50
336:43.46
325:43.32
314:43.38
303:43.34
292:43.30
281:43.26
223:fooled
156:pagers
2822:South
2817:North
2778:JANET
2715:Telex
2705:Radio
2544:Nodes
2539:Links
2460:media
2038:Radio
2023:Pager
1951:Drums
1917:video
1912:image
1902:audio
1760:ViLTE
1755:VoLTE
1713:5G NR
1662:STDMA
1650:OFDMA
1593:Other
1579:LTE-M
1564:5G NR
1527:WiBro
1514:WiMAX
1433:WiBro
1346:HSPA+
1339:HSUPA
1334:HSDPA
1217:WiDEN
1210:Other
1113:Other
1076:3GPP2
1009:Hicap
1004:C-450
992:Other
909:Altai
377:35.66
366:35.62
355:35.54
344:35.50
333:35.46
322:35.42
311:35.38
300:35.34
289:35.30
278:35.26
58:radio
2834:Asia
2720:UUCP
2680:ISDN
1770:ViNR
1765:VoNR
1745:MIMO
1718:CDMA
1703:UMTS
1681:SDMA
1674:CDMA
1669:SSMA
1657:TDMA
1645:FDMA
1443:ETSI
1402:IEEE
1329:HSPA
1267:FOMA
1257:UMTS
1222:DECT
1174:GPRS
1125:iDEN
1120:CDPD
1095:AMPS
1052:3GPP
969:AMPS
929:AMTS
904:IMTS
70:land
44:IMTS
38:The
2725:WAN
2695:NGN
2685:LAN
1966:Fax
1907:DCT
1750:IMS
1708:LTE
1698:GSM
1358:LTE
1165:GSM
1140:CT2
1135:PHS
1130:PDC
1061:GSM
1048:GSM
1024:CT1
999:NMT
949:AMR
939:ARP
914:OLT
899:MTS
706:by
177:NPA
114:by
55:UHF
51:VHF
2918::
1543:5G
1520:)
1466:4G
1236:3G
1038:2G
959:1G
887:0G
663:QF
652:QY
641:QR
630:QO
619:QB
608:QK
597:QP
586:QE
575:QA
564:QD
553:QJ
542:QC
524:JW
513:JR
502:JK
491:YR
480:YS
469:JS
458:YK
447:YJ
436:YP
425:JP
414:YL
403:JL
392:JJ
374:ZL
363:ZW
352:ZB
341:ZR
330:ZY
319:ZA
308:ZM
297:ZH
286:ZF
275:ZO
2852:)
2848:(
1843:e
1836:t
1829:v
1516:(
1493:)
1489:(
1364:)
1360:(
1050:/
861:e
854:t
847:v
817:.
729:)
723:(
718:)
714:(
700:.
137:)
131:(
126:)
122:(
108:.
53:/
42:(
20:)
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