224:
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.
182:
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.
1795:
173:
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.
164:
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
20:
169:
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.
2866:
732:
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.
675:
83:
2876:
2855:
1784:
2886:
206:, 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.
147:" 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.
181:
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
172:
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
159:
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
735:
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
214:
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
168:
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
223:
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
194:
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
135:
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"
163:
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
236:
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
195:
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.
727:
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
731:
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.
209:
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
150:
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
185:
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
215:
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.
140:) 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.
736:
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.
912:
2130:
848:
202:, 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
692:
100:
1390:
2910:
1411:
1758:
1638:
2838:
2810:
2805:
1830:
1650:
1210:
792:
937:
1588:
1562:
841:
240:
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.
2832:
1718:
2915:
2827:
2817:
2797:
2599:
1167:
1623:
1064:
1964:
2889:
2822:
2668:
1255:
834:
2594:
1633:
2688:
1322:
971:
714:
122:
66:
50:
728:
subscribers to disconnect their subscription in order to obtain a mobile telephone number and mobile phone service.
65:(MTS) and improved on most MTS systems by offering direct-dial rather than connections through a live operator, and
2473:
2021:
1823:
1334:
917:
867:
2584:
1723:
1327:
897:
2579:
1669:
696:
104:
2604:
1662:
1645:
165:
2879:
2640:
2537:
2080:
1875:
1847:
1162:
1108:
1083:
966:
957:
745:
155:
since a radio closer to the terminal would sometimes take over the channel because of its stronger signal.
1676:
2869:
2376:
1816:
1123:
2728:
2650:
2589:
2296:
2500:
2461:
2306:
2206:
2135:
2068:
1895:
1118:
764:, the earliest 'car telephone' service provided by the Bell System, later replaced by IMTS technology
2859:
2101:
2036:
1989:
1949:
1788:
1618:
1380:
1374:
1368:
1317:
1285:
887:
761:
233:
62:
2698:
2683:
2527:
2478:
2401:
2301:
1979:
1865:
1860:
1738:
1346:
987:
685:
152:
93:
796:
2620:
2406:
2221:
2166:
2161:
1974:
1939:
1763:
875:
756:
2522:
2326:
2291:
2211:
2191:
2113:
2001:
1922:
1701:
1628:
1054:
1855:
2436:
2396:
2366:
2123:
2058:
1880:
1706:
1691:
1681:
907:
902:
43:
8:
2446:
2386:
2145:
2107:
1905:
1890:
1696:
1686:
39:
2673:
2630:
2561:
2431:
2361:
2336:
2271:
2118:
1839:
232:
The frequencies listed below (in MHz) are those formerly used in the US & Canadian
137:
2713:
2635:
2549:
2532:
2495:
2341:
2171:
2140:
2006:
1900:
1799:
2381:
2718:
2678:
2658:
2625:
2554:
2512:
2426:
2281:
2266:
2241:
2216:
2176:
2026:
1885:
1870:
1713:
1613:
1608:
1485:
927:
857:
156:
36:
2346:
2201:
1969:
1944:
1932:
1657:
2544:
2416:
2391:
2351:
2321:
2196:
2031:
1984:
1959:
1917:
1748:
1743:
1572:
1189:
878:
767:
54:
2904:
2693:
2466:
2456:
2371:
2261:
2256:
2246:
2231:
2053:
1912:
1753:
826:
772:
2571:
2411:
2356:
2286:
2251:
2186:
2085:
2075:
1927:
1728:
1475:
1459:
1092:
187:
19:
2771:
2421:
2331:
2316:
2276:
2236:
2095:
1557:
1506:
1416:
1404:
2776:
2483:
2181:
2090:
2046:
2016:
1994:
699: in this section. Unsourced material may be challenged and removed.
107: in this section. Unsourced material may be challenged and removed.
1183:
2761:
2226:
2041:
1808:
751:
674:
82:
2756:
2746:
2663:
2488:
2311:
1536:
1440:
1339:
1262:
1229:
191:
58:
2751:
2736:
1954:
1770:
1300:
1267:
1142:
1073:
1007:
1002:
922:
820:
143:
RCCs were also allowed to offer paging services to "beepers" or "
2781:
2741:
2063:
1479:
1350:
1250:
992:
932:
237:
services unrelated to mobile telephony and largely reassigned.
144:
2766:
2703:
2011:
1567:
1552:
1515:
1502:
1421:
1399:
1205:
997:
46:
2708:
1733:
1431:
1245:
1113:
1040:
1153:
1128:
1049:
1036:
1012:
1531:
1454:
1224:
1026:
947:
69:
operation so both parties could talk at the same time.
61:
dial phone service. Introduced in 1964, it replaced
2902:
856:
1824:
842:
2839:Global telecommunications regulation bodies
136:and "UHF". In addition to the Bell system (
2875:
1831:
1817:
849:
835:
715:Learn how and when to remove this message
123:Learn how and when to remove this message
72:
18:
2911:Telecommunications in the United States
2903:
1838:
1719:Multimedia Broadcast Multicast Service
1812:
830:
2885:
1677:Spectral efficiency comparison table
697:adding citations to reliable sources
668:
105:adding citations to reliable sources
76:
13:
14:
2927:
814:
29:Improved Mobile Telephone Service
23:IMTS mobile phone in a briefcase.
2884:
2874:
2865:
2864:
2853:
2474:Free-space optical communication
1793:
1782:
868:List of mobile phone generations
673:
190:looked much like those used for
81:
684:needs additional citations for
218:
92:needs additional citations for
16:Early mobile telephone standard
785:
664:
227:
1:
793:"2005 CFR Title 47, Volume 2"
778:
2916:Telecommunications in Canada
2860:Telecommunication portal
2641:Telecommunications equipment
1789:Telecommunication portal
746:Advanced Mobile Phone System
7:
2377:Alexander Stepanovich Popov
739:
242:
176:
49:system which linked to the
10:
2932:
2081:Telecommunications history
1286:CDMA2000 1xEV-DO Release 0
823:- overview of MTS and IMTS
2848:
2790:
2727:
2689:Public Switched Telephone
2649:
2613:
2570:
2511:
2501:telecommunication circuit
2462:Fiber-optic communication
2445:
2207:Francis Blake (telephone)
2154:
2002:Optical telecommunication
1846:
1779:
1601:
1581:
1545:
1530:
1495:
1468:
1453:
1430:
1389:
1360:
1310:
1299:
1278:
1238:
1223:
1198:
1176:
1168:EDGE/EGPRS - Evolved EDGE
1152:
1141:
1101:
1093:D-AMPS (IS-54 and IS-136)
1082:
1063:
1035:
1025:
980:
956:
946:
874:
865:
523:
373:
256:
160:sparsely-populated area.
2600:Orbital angular-momentum
2037:Satellite communications
1876:Communications satellite
762:Mobile Telephone Service
234:Mobile Telephone Service
63:Mobile Telephone Service
51:public telephone network
2479:Molecular communication
2302:Gardiner Greene Hubbard
2131:Undersea telegraph line
1866:Cable protection system
1624:Comparison of standards
1263:UTRA-TDD LCR / TD-SCDMA
2621:Communication protocol
2407:Charles Sumner Tainter
2222:Walter Houser Brattain
2167:Edwin Howard Armstrong
1975:Information revolution
1629:Channel access methods
1268:UTRA-TDD HCR / TD-CDMA
757:Mobile radio telephone
24:
2595:Polarization-division
2327:Narinder Singh Kapany
2292:Erna Schneider Hoover
2212:Jagadish Chandra Bose
2192:Alexander Graham Bell
1923:online video platform
1800:Telephones portal
908:MTA - MTB - MTC - MTD
73:Technical Information
22:
2437:Vladimir K. Zworykin
2397:Almon Brown Strowger
2367:Charles Grafton Page
2022:Prepaid mobile phone
1950:Electrical telegraph
1417:iBurst (IEEE 802.20)
1190:CDMA2000 1X Advanced
821:THE MOBILE TELEPHONE
693:improve this article
198:The IMTS units were
101:improve this article
2387:Johann Philipp Reis
2146:Wireless revolution
2108:The Telephone Cases
1965:Hydraulic telegraph
1303:(3.5G, 3.75G, 3.9G)
1145:(2.5G, 2.75G, 2.9G)
913:Mobile TeleSeratout
2585:Frequency-division
2562:Telephone exchange
2432:Charles Wheatstone
2362:Jun-ichi Nishizawa
2337:Innocenzo Manzetti
2272:Reginald Fessenden
2007:Optical telegraphy
1840:Telecommunications
1791:
1377:(TIA/EIA/IS-856-B)
1371:(TIA/EIA/IS-856-A)
1369:1xEV-DO Revision A
138:wireline incumbent
25:
2898:
2897:
2636:Store and forward
2631:Data transmission
2545:Network switching
2496:Transmission line
2342:Guglielmo Marconi
2307:Internet pioneers
2172:Mohamed M. Atalla
2141:Whistled language
1806:
1805:
1609:Cellular networks
1597:
1596:
1526:
1525:
1449:
1448:
1295:
1294:
1251:UTRA-FDD / W-CDMA
1219:
1218:
1186:(TIA/EIA/IS-2000)
1137:
1136:
1021:
1020:
725:
724:
717:
662:
661:
252:Mobile frequency
157:Cellular networks
133:
132:
125:
2923:
2888:
2887:
2878:
2877:
2868:
2867:
2858:
2857:
2856:
2729:Notable networks
2719:Wireless network
2659:Cellular network
2651:Types of network
2626:Computer network
2513:Network topology
2427:Thomas A. Watson
2282:Oliver Heaviside
2267:Philo Farnsworth
2242:Daniel Davis Jr.
2217:Charles Bourseul
2177:John Logie Baird
1886:Data compression
1881:Computer network
1833:
1826:
1819:
1810:
1809:
1798:
1797:
1796:
1787:
1786:
1785:
1714:Mobile broadband
1614:Mobile telephony
1602:Related articles
1543:
1542:
1486:LTE Advanced Pro
1466:
1465:
1381:EV-DO Revision C
1375:EV-DO Revision B
1308:
1307:
1236:
1235:
1150:
1149:
1033:
1032:
954:
953:
879:radio telephones
858:Cellular network
851:
844:
837:
828:
827:
808:
807:
805:
804:
795:. Archived from
789:
720:
713:
709:
706:
700:
677:
669:
243:
128:
121:
117:
114:
108:
85:
77:
53:. IMTS was the
2931:
2930:
2926:
2925:
2924:
2922:
2921:
2920:
2901:
2900:
2899:
2894:
2854:
2852:
2844:
2786:
2723:
2645:
2609:
2566:
2515:
2507:
2448:
2441:
2347:Robert Metcalfe
2202:Tim Berners-Lee
2150:
1970:Information Age
1842:
1837:
1807:
1802:
1794:
1792:
1783:
1781:
1775:
1682:Frequency bands
1593:
1577:
1535:
1522:
1491:
1458:
1445:
1426:
1385:
1356:
1302:
1301:3G transitional
1291:
1274:
1228:
1215:
1194:
1172:
1144:
1143:2G transitional
1133:
1097:
1078:
1074:cdmaOne (IS-95)
1059:
1017:
976:
942:
870:
861:
855:
817:
812:
811:
802:
800:
791:
790:
786:
781:
742:
721:
710:
704:
701:
690:
678:
667:
230:
221:
179:
129:
118:
112:
109:
98:
86:
75:
17:
12:
11:
5:
2929:
2919:
2918:
2913:
2896:
2895:
2893:
2892:
2882:
2872:
2862:
2849:
2846:
2845:
2843:
2842:
2835:
2830:
2825:
2820:
2815:
2814:
2813:
2808:
2800:
2794:
2792:
2788:
2787:
2785:
2784:
2779:
2774:
2769:
2764:
2759:
2754:
2749:
2744:
2739:
2733:
2731:
2725:
2724:
2722:
2721:
2716:
2711:
2706:
2701:
2696:
2691:
2686:
2681:
2676:
2671:
2666:
2661:
2655:
2653:
2647:
2646:
2644:
2643:
2638:
2633:
2628:
2623:
2617:
2615:
2611:
2610:
2608:
2607:
2602:
2597:
2592:
2587:
2582:
2580:Space-division
2576:
2574:
2568:
2567:
2565:
2564:
2559:
2558:
2557:
2552:
2542:
2541:
2540:
2530:
2525:
2519:
2517:
2509:
2508:
2506:
2505:
2504:
2503:
2493:
2492:
2491:
2481:
2476:
2471:
2470:
2469:
2459:
2453:
2451:
2443:
2442:
2440:
2439:
2434:
2429:
2424:
2419:
2417:Camille Tissot
2414:
2409:
2404:
2399:
2394:
2392:Claude Shannon
2389:
2384:
2382:Tivadar Puskás
2379:
2374:
2369:
2364:
2359:
2354:
2352:Antonio Meucci
2349:
2344:
2339:
2334:
2329:
2324:
2322:Charles K. Kao
2319:
2314:
2309:
2304:
2299:
2297:Harold Hopkins
2294:
2289:
2284:
2279:
2274:
2269:
2264:
2259:
2254:
2249:
2244:
2239:
2234:
2229:
2224:
2219:
2214:
2209:
2204:
2199:
2197:Emile Berliner
2194:
2189:
2184:
2179:
2174:
2169:
2164:
2158:
2156:
2152:
2151:
2149:
2148:
2143:
2138:
2136:Videotelephony
2133:
2128:
2127:
2126:
2121:
2111:
2104:
2099:
2093:
2088:
2083:
2078:
2073:
2072:
2071:
2066:
2061:
2051:
2050:
2049:
2039:
2034:
2032:Radiotelephone
2029:
2024:
2019:
2014:
2009:
2004:
1999:
1998:
1997:
1987:
1982:
1977:
1972:
1967:
1962:
1957:
1952:
1947:
1942:
1937:
1936:
1935:
1930:
1925:
1920:
1918:Internet video
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923:Autotel (PALM)
920:
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895:
890:
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872:
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815:External links
813:
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783:
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777:
776:
775:
770:
768:Radiotelephone
765:
759:
754:
749:
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723:
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681:
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672:
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249:Base frequency
247:
229:
226:
220:
217:
178:
175:
131:
130:
89:
87:
80:
74:
71:
57:equivalent of
55:radiotelephone
15:
9:
6:
4:
3:
2:
2928:
2917:
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2619:
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2612:
2606:
2605:Code-division
2603:
2601:
2598:
2596:
2593:
2591:
2590:Time-division
2588:
2586:
2583:
2581:
2578:
2577:
2575:
2573:
2569:
2563:
2560:
2556:
2553:
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2543:
2539:
2536:
2535:
2534:
2531:
2529:
2526:
2524:
2521:
2520:
2518:
2516:and switching
2514:
2510:
2502:
2499:
2498:
2497:
2494:
2490:
2487:
2486:
2485:
2482:
2480:
2477:
2475:
2472:
2468:
2467:optical fiber
2465:
2464:
2463:
2460:
2458:
2457:Coaxial cable
2455:
2454:
2452:
2450:
2444:
2438:
2435:
2433:
2430:
2428:
2425:
2423:
2420:
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2400:
2398:
2395:
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2378:
2375:
2373:
2372:Radia Perlman
2370:
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2283:
2280:
2278:
2275:
2273:
2270:
2268:
2265:
2263:
2262:Lee de Forest
2260:
2258:
2257:Thomas Edison
2255:
2253:
2250:
2248:
2247:Donald Davies
2245:
2243:
2240:
2238:
2235:
2233:
2232:Claude Chappe
2230:
2228:
2225:
2223:
2220:
2218:
2215:
2213:
2210:
2208:
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2203:
2200:
2198:
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2178:
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2173:
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2163:
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2110:
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2103:
2100:
2097:
2094:
2092:
2089:
2087:
2084:
2082:
2079:
2077:
2076:Smoke signals
2074:
2070:
2067:
2065:
2062:
2060:
2057:
2056:
2055:
2054:Semiconductor
2052:
2048:
2045:
2044:
2043:
2040:
2038:
2035:
2033:
2030:
2028:
2025:
2023:
2020:
2018:
2015:
2013:
2010:
2008:
2005:
2003:
2000:
1996:
1993:
1992:
1991:
1988:
1986:
1983:
1981:
1978:
1976:
1973:
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1968:
1966:
1963:
1961:
1958:
1956:
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1943:
1941:
1938:
1934:
1931:
1929:
1926:
1924:
1921:
1919:
1916:
1915:
1914:
1913:Digital media
1911:
1907:
1904:
1902:
1899:
1897:
1894:
1892:
1889:
1888:
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1884:
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1822:
1820:
1815:
1814:
1811:
1801:
1790:
1778:
1772:
1769:
1765:
1764:Wi-Fi Calling
1762:
1760:
1757:
1755:
1752:
1750:
1747:
1745:
1742:
1741:
1740:
1737:
1735:
1732:
1730:
1727:
1725:
1724:NGMN Alliance
1722:
1720:
1717:
1715:
1712:
1708:
1705:
1703:
1700:
1698:
1695:
1693:
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1590:
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1569:
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1517:
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1500:
1498:
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1471:
1467:
1464:
1461:
1456:
1452:
1442:
1439:
1438:
1436:
1433:
1429:
1423:
1420:
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1415:
1413:
1410:
1406:
1403:
1402:
1401:
1398:
1397:
1395:
1392:
1388:
1382:
1379:
1376:
1373:
1370:
1366:
1365:
1363:
1359:
1352:
1348:
1345:
1341:
1338:
1337:
1336:
1333:
1329:
1326:
1324:
1321:
1320:
1319:
1316:
1315:
1313:
1309:
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1304:
1298:
1287:
1284:
1283:
1281:
1277:
1269:
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1264:
1261:
1257:
1254:
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1249:
1248:
1247:
1244:
1243:
1241:
1237:
1234:
1231:
1226:
1222:
1212:
1209:
1207:
1204:
1203:
1201:
1197:
1191:
1188:
1185:
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1181:
1179:
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1169:
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1164:
1161:
1160:
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1140:
1130:
1127:
1125:
1122:
1120:
1117:
1115:
1112:
1110:
1107:
1106:
1104:
1100:
1094:
1091:
1090:
1088:
1085:
1081:
1075:
1072:
1071:
1069:
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1062:
1056:
1053:
1051:
1048:
1047:
1045:
1042:
1038:
1034:
1031:
1028:
1024:
1014:
1011:
1009:
1006:
1004:
1001:
999:
996:
994:
991:
989:
986:
985:
983:
979:
973:
970:
968:
967:AMPS - N-AMPS
965:
964:
962:
959:
955:
952:
949:
945:
939:
936:
934:
931:
929:
926:
924:
921:
919:
916:
914:
911:
909:
906:
904:
901:
899:
896:
894:
891:
889:
886:
885:
883:
880:
877:
873:
869:
864:
859:
852:
847:
845:
840:
838:
833:
832:
829:
822:
819:
818:
799:on 2008-02-07
798:
794:
788:
784:
774:
773:Two-way radio
771:
769:
766:
763:
760:
758:
755:
753:
750:
747:
744:
743:
737:
733:
729:
719:
716:
708:
698:
694:
688:
687:
682:This section
680:
676:
671:
670:
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:
536:
533:
530:
529:
526:
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:
386:
383:
380:
379:
376:
375:VHF High Band
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:
269:
266:
263:
262:
259:
255:
251:
248:
245:
244:
241:
238:
235:
225:
216:
213:
207:
205:
201:
196:
193:
189:
188:whip antennas
183:
174:
170:
167:
161:
158:
154:
148:
146:
141:
139:
127:
124:
116:
106:
102:
96:
95:
90:This section
88:
84:
79:
78:
70:
68:
64:
60:
56:
52:
48:
45:
41:
38:
34:
30:
21:
2572:Multiplexing
2447:Transmission
2412:Nikola Tesla
2402:Henry Sutton
2357:Samuel Morse
2287:Robert Hooke
2252:Amos Dolbear
2187:John Bardeen
2106:
2086:Telautograph
1990:Mobile phone
1945:Edholm's law
1928:social media
1861:Broadcasting
1729:Push-to-talk
1507:IEEE 802.16m
1476:LTE Advanced
1460:IMT Advanced
1405:IEEE 802.16e
1400:Mobile WiMAX
1361:3GPP2 family
1288:(TIA/IS-856)
1279:3GPP2 family
1177:3GPP2 family
1156:/3GPP family
972:TACS - ETACS
892:
801:. Retrieved
797:the original
787:
734:
730:
726:
711:
702:
691:Please help
686:verification
683:
524:
374:
258:VHF Low Band
257:
239:
231:
222:
219:Base station
211:
208:
203:
199:
197:
184:
180:
171:
162:
153:interference
149:
142:
134:
119:
110:
99:Please help
94:verification
91:
35:) was a pre-
32:
28:
26:
2772:NPL network
2484:Radio waves
2422:Alfred Vail
2332:Hedy Lamarr
2317:Dawon Kahng
2277:Elisha Gray
2237:Yogen Dalal
2162:Nasir Ahmed
2096:Teleprinter
1960:Heliographs
1558:5G-Advanced
1546:3GPP family
1496:IEEE family
1488:(4.5G/4.9G)
1469:3GPP family
1311:3GPP family
1239:3GPP family
1184:CDMA2000 1X
1055:CSD - HSCSD
748:, successor
665:Limitations
228:Frequencies
204:half duplex
200:full duplex
67:full-duplex
2905:Categories
2818:Antarctica
2777:Toasternet
2699:Television
2182:Paul Baran
2114:Television
2098:(teletype)
2091:Telegraphy
2069:transistor
2047:Phryctoria
2017:Photophone
1995:Smartphone
1985:Mass media
1412:Flash-OFDM
803:2009-10-16
779:References
705:April 2016
113:April 2016
2802:Americas
2791:Locations
2762:Internet2
2523:Bandwidth
2227:Vint Cerf
2124:streaming
2102:Telephone
2042:Semaphore
1933:streaming
1512:WiMax 2.1
1367:CDMA2000
860:standards
752:Car phone
192:CB radios
2870:Category
2757:Internet
2747:CYCLADES
2664:Ethernet
2614:Concepts
2538:terminal
2489:wireless
2312:Bob Kahn
2155:Pioneers
1980:Internet
1871:Cable TV
1537:IMT-2020
1441:HiperMAN
1340:DC-HSDPA
1230:IMT-2000
740:See also
658:459.650
647:459.625
636:459.600
625:459.575
614:459.550
603:459.525
592:459.500
581:459.475
570:459.450
559:459.425
548:459.400
537:459.375
525:UHF Band
177:Terminal
37:cellular
2890:Commons
2880:Outline
2833:Oceania
2752:FidoNet
2737:ARPANET
2550:circuit
2119:digital
1848:History
1771:Osmocom
1619:History
1589:DECT-5G
1563:NR-IIoT
1008:DataTAC
1003:Mobitex
655:454.650
644:454.625
633:454.600
622:454.575
611:454.550
600:454.525
589:454.500
578:454.475
567:454.450
556:454.425
545:454.400
534:454.375
519:158.10
508:158.07
497:158.04
486:158.01
475:157.98
464:157.95
453:157.92
442:157.89
431:157.86
420:157.83
409:157.80
398:157.77
387:157.74
246:Channel
2828:Europe
2798:Africa
2782:Usenet
2742:BITNET
2679:Mobile
2555:packet
2064:MOSFET
2059:device
1856:Beacon
1573:NB-IoT
1539:(2021)
1534:(2018)
1480:E-UTRA
1462:(2013)
1457:(2009)
1434:family
1393:family
1351:E-UTRA
1232:(2001)
1227:(1998)
1086:family
1067:family
1043:family
1029:(1991)
960:family
950:(1979)
933:B-Netz
881:(1946)
516:152.84
505:152.81
494:152.78
483:152.75
472:152.72
461:152.69
450:152.66
439:152.63
428:152.60
417:152.57
406:152.54
395:152.51
384:152.48
369:43.66
358:43.62
347:43.54
336:43.50
325:43.46
314:43.32
303:43.38
292:43.34
281:43.30
270:43.26
212:fooled
145:pagers
2811:South
2806:North
2767:JANET
2704:Telex
2694:Radio
2533:Nodes
2528:Links
2449:media
2027:Radio
2012:Pager
1940:Drums
1906:video
1901:image
1891:audio
1749:ViLTE
1744:VoLTE
1702:5G NR
1651:STDMA
1639:OFDMA
1582:Other
1568:LTE-M
1553:5G NR
1516:WiBro
1503:WiMAX
1422:WiBro
1335:HSPA+
1328:HSUPA
1323:HSDPA
1206:WiDEN
1199:Other
1102:Other
1065:3GPP2
998:Hicap
993:C-450
981:Other
898:Altai
366:35.66
355:35.62
344:35.54
333:35.50
322:35.46
311:35.42
300:35.38
289:35.34
278:35.30
267:35.26
47:radio
2823:Asia
2709:UUCP
2669:ISDN
1759:ViNR
1754:VoNR
1734:MIMO
1707:CDMA
1692:UMTS
1670:SDMA
1663:CDMA
1658:SSMA
1646:TDMA
1634:FDMA
1432:ETSI
1391:IEEE
1318:HSPA
1256:FOMA
1246:UMTS
1211:DECT
1163:GPRS
1114:iDEN
1109:CDPD
1084:AMPS
1041:3GPP
958:AMPS
918:AMTS
893:IMTS
59:land
33:IMTS
27:The
2714:WAN
2684:NGN
2674:LAN
1955:Fax
1896:DCT
1739:IMS
1697:LTE
1687:GSM
1347:LTE
1154:GSM
1129:CT2
1124:PHS
1119:PDC
1050:GSM
1037:GSM
1013:CT1
988:NMT
938:AMR
928:ARP
903:OLT
888:MTS
695:by
166:NPA
103:by
44:UHF
40:VHF
2907::
1532:5G
1509:)
1455:4G
1225:3G
1027:2G
948:1G
876:0G
652:QF
641:QY
630:QR
619:QO
608:QB
597:QK
586:QP
575:QE
564:QA
553:QD
542:QJ
531:QC
513:JW
502:JR
491:JK
480:YR
469:YS
458:JS
447:YK
436:YJ
425:YP
414:JP
403:YL
392:JL
381:JJ
363:ZL
352:ZW
341:ZB
330:ZR
319:ZY
308:ZA
297:ZM
286:ZH
275:ZF
264:ZO
2841:)
2837:(
1832:e
1825:t
1818:v
1505:(
1482:)
1478:(
1353:)
1349:(
1039:/
850:e
843:t
836:v
806:.
718:)
712:(
707:)
703:(
689:.
126:)
120:(
115:)
111:(
97:.
42:/
31:(
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