159:
The fleetmap lays out the various talkgroups that the agency requires to successfully undertake its business. For example, in an ambulance service fleetmap there will be a talkgroup created for each of the hospital ER's that the ambulances interact with; talkgroups for communications with dispatch(s), talkgroups for special events or disasters, a talkgroup for air medical transport, and a number of talkgroups that are shared (with appropriate controls) with other first response agencies such as police and fire services. Each talkgroup is assigned a unique digital ID on the system so that the controller can direct transmissions to the radios which are intended to receive them. Within the same shared system there can be a fleet of ambulances, a fleet of police users, and a fleet of firefighters. In most shared public safety/public service systems, whether city-wide, or state/province-wide, there are often additional users sharing the system at a pre-determined lower priority for service such as animal control, public works, highways maintenance, correctional services, natural resources, etc. The system may also include talkgroups for federal agencies operating within the jurisdiction and in some cases commercial users which provide assistance to general public safety. These fleetmaps are considered subfleets of the actual talkgroups. The subfleets are intuitively programmed into the users' radios so that the users can easily find a talkgroup when s/he is required to switch for a particular situation. Alternatively, a trunking system dispatch console operator can actually 'patch' two talkgroups together making a new 'virtual' talkgroup to allow users from different agencies to communicate without having to switch channels.
51:) with mobile and portable two-way radios communicate over a single shared radio channel, with one user at a time talking. These systems typically have access to multiple channels, up to 40-60, so multiple groups in the same area can communicate simultaneously. In a conventional (non-trunked) system, channel selection is done manually; before use, the group must decide which channel to use, and manually switch all the radios to that channel. This is an inefficient use of scarce radio channel resources because the user group must have exclusive use of their channel regardless of how much or how little they are transmitting. There is also nothing to prevent multiple groups in the same area from choosing the same channel, causing conflicts and 'cross-talk'. A trunked radio system is an advanced alternative in which the channel selection process is done automatically, so as to avoid channel conflicts and maintain frequency efficiency across multiple talkgroups. This process is handed by what is essentially a central
163:
and a fire service block on the same system might begin with 102200 up to 102299. This identifies the system as 102XXX and provides one hundred talkgroup ID's for each agency. Agency-shared talkgroups (sometimes referred to as Mutual Aid or Inter-agency) may be assigned a block starting at 102500 up to 102520, allowing for twenty shared talkgroups that can be offered for use by any authorized agency. In many province-wide systems, it is mandatory for participation in the system for user agencies to include all of the authorized shared talkgroups and/or shared simplex frequencies.
63:. When any user in that group wishes to communicate with another user in the talkgroup, an idle radio channel is found automatically by the system and the conversation takes place on that channel. Many unrelated conversations can occur on a channel, making use of the otherwise idle time between conversations. Each radio transceiver contains a microprocessor that handles the channel selection process. A control channel coordinates all the activity of the radios in the system. The control channel computer sends packets of data to enable one
20:
193:
the telephone and radio systems. In both cases once the trunking capacity of the systems is fully used, all subsequent users will receive a busy signal. In such a case management of communications becomes critical with only very local communications sharing simplex (non-system) frequencies, and longer distance communications sharing pre-planned trunking talkgroups and governing use of the resources to essential communications.
121:— to request communication on a specific talkgroup. The controller sends a signal to all radios monitoring that talkgroup, instructing the radios to automatically switch to the frequency indicated by the system to monitor the transmission. After the user is done speaking, the users' radios return to monitoring the control channel for additional transmissions.
217:
Trunked radio takes advantage of the probability that with any given number of users, not everyone will need channel access at the same time, therefore fewer discrete radio channels are required. From another perspective, with a given number of radio channels, a much greater number of user groups can
208:
For example, if police communications are configured in such a way that twelve conventional channels are required to permit citywide dispatch based upon geographical patrol areas, during periods of slow dispatch activity, much of that channel capacity is idle. In a trunked system, the police units in
162:
Generally in planning a multi-agency trunking radio system, each agency is assigned a 'block' of talkgroup ID numbers based on the number of talkgroups they anticipate requiring, plus some excess for future expansion. Thus a police service block of talkgroup ID's might begin with 102100 up to 102199,
221:
To the user, a trunking radio looks just like an 'ordinary' radio: there is a 'channel select switch' for the user to select the 'channel' that they want to use. In reality though, the 'channel switch' is not switching frequencies as in a conventional radio but when changed, it refers to an internal
306:
area used by crop harvesting crews may overload and experience busy signals during peaks in harvesting. A system used by a ski resort may overload on a holiday weekend. Disaster planning experts like to say that trunked system users are likely to hear busy signals for the first time when a disaster
158:
Each system is built with a number of system talkgroups identified as required by the planned user agencies, to which new talkgroups can easily be added as the system matures and new agencies or new requirements are identified. For each user agency, talkgroups are assigned in an agency 'fleetmap'.
610:
SMR systems are not designed and built to the same standards as government trunked systems used to manage emergencies. There are many documents addressing this issue. One article discussing this topic is, "Intra- and Inter-County
Coordination and Interoperability: Existing Cooperative Agreements,"
430:
These systems exhibit some of the characteristics of a high tier trunked radio system but not all features. Therefore, they are suitable for small deployments where users are expected to use the entire network available (such as a private system covering a campus or town). Because of their lack of
192:
This concept has been simply applied to radio user groups, to determine the optimal number of channels needed, under normal conditions, to accommodate a given number of users. In the event of a widespread emergency such as a major earthquake, many more users than normal will attempt to access both
171:
Most scanners that can listen to trunked radio systems (called trunk tracking) are able to scan and store individual talkgroups just as if they were frequencies. The difference in this case is that the groups are assigned to a certain bank in which the trunked system is programmed. In other words,
334:
These systems are relatively simple in their operation and only meet the minimum requirements to be defined as a 'trunked' radio system. They generally do not have enhanced features such as data communications or registration awareness. They will provide simple trunking facilities for voice calls
58:
Trunking is a more automated and complex radio system, but provides the benefits of less user intervention to operate the radio and greater spectral efficiency with large numbers of users. Instead of assigning a radio channel to one particular user group at a time, users are instead assigned to a
180:
The concept of trunking (resource sharing) is actually quite old, and is taken from telephone company technology and practice. Consider two telco central office exchanges, one in town "A" and the other in adjacent town "B". Each of these central offices has the theoretical capacity to handle ten
205:'Trunked' radio systems differ from 'conventional' radio systems in that a conventional radio system uses a dedicated channel (frequency) for each individual group of users, while 'trunking' radio systems use a pool of channels which are available for a great many different groups of users.
298:
In SMR systems, many factors affect the quality of service. This may include the capacity of the radio system versus the number of radio units using the system. A talkative user community may cause busy signals while a disciplined, professional group of SMR users may keep channels idle.
218:
be accommodated. In the example of the police department, this additional capacity could then be used to assign individual talkgroups to specialized investigative, traffic control, or special-events groups which might otherwise not have the benefit of individual private communications.
438:
DMR/dPMR true Tier 3/Mode 3 protocols are intended eventually to migrate into the "Advanced Mature high end" list below but today (2015) cannot be classified as such due to major interoperability issues, lack of mature protocol and lack of clearly defined user interface protocol.
222:
software program which causes a new talkgroup affiliation to be transmitted on the control channel. This identifies the specific radio to the system controller as a member of a specific talkgroup, and that radio will then be included in any conversations involving that talkgroup.
145:
coordinates the system so talkgroups can share these frequencies seamlessly. The purpose is to dramatically increase system capacity with optimal use of frequencies. Many radios today treat talkgroups as if they were frequencies, since they behave like such. For example, on a
184:
If all 10,000 subscribers in "A" were to simultaneously call 10,000 subscribers in "B", then it would be necessary to have 10,000 lines to connect the two towns. However, the odds of that happening are remote, as the number of simultaneous phone calls is usually much lower.
596:
The date is unclear. The FCC web site has a page under the
Wireless Telecommunication Bureau defining Specialized Mobile Radio Service. It claims licenses were first issued in 1979. Another publication suggests licenses were first issued in 1976. See: "3.6.1 Overview,"
314:
should overlook the desired coverage area. Federal
Communications Commission regulations require systems using the same radio frequency to be spaced 70 miles from one another or do an engineering study to confirm there will be no interference from closer spacing.
326:. This is a measurement of the sound quality over all of the involved pieces of communications equipment from end to end. The first clue this may be an issue is that radio users with normal hearing have trouble understanding others when speaking over the radio.
124:
This arrangement allows multiple groups of users to share a small set of actual radio frequencies without hearing each other's conversations. Trunked systems primarily conserve limited radio frequencies and also provide other advanced features to users.
225:
This also allows great flexibility in radio usage – the same radio model can be used for many different types of system users (i.e. Police, Fire, Public Works, Animal
Control, etc.) simply by changing the software programming in the radio itself.
23:
A central-controlled trunked system uses a control channel (as shown). Another type, scan based trunked systems, (not shown) do not have a control channel. Frequencies are for discussion purposes and do not correspond to any specific
229:
Since the talkgroups are constantly transmitting on different frequencies, trunked radio systems makes it more difficult for a scanner listener without a programmed trunk tracking scanner to keep up with the conversation.
196:
In our example of police dispatch, different talkgroups are assigned different system priority levels, sometimes with 'preemption' capability, attempting to ensure that communication between critical units is maintained.
94:, or other entity. A secondary benefit of a trunking radio system is the ease with which it can accommodate radio interoperability and with proper planning, add authorized user agencies to the system post-implementation.
249:
This is not designed to be a list of manufacturers' equipment types, it is intended as a list of air protocol types unless significant vendor specific modifications have been made which violate the published standard.
318:
Maintenance practices also can affect quality. In some systems, the operator may remove one channel of a trunked system from service to perform repairs. In a heavily used system, this could cause busy signals.
565:
from the
Department of Homeland Security analyzes and compares conventional, trunked, and hybrid LMR systems and provides high-level definitions of the architecture alternatives associated with each option.
181:
thousand individual telephone numbers. (Central office "A", with prefix "123", has available 10,000 numbers from 123-0000 to 123-9999; central office "B", with prefix "124", the same.)
287:
regulations. The term is of US regulatory origin but may be used in other regions to describe similar commercial systems which offer a radio communications service to businesses.
209:
a given geographical area are not assigned a dedicated channel, but instead are members of a talk-group entitled to draw upon the common resources of a smaller pool of channels.
253:
Trunked radio technologies today have generally diverged into three distinct types or 'tiers'. These are not 'official', but are clearly defined within protocol types:-
70:
The primary purpose of this type of system is efficiency; many people can carry many conversations over only a few distinct frequencies. Trunking is used by many
290:
SMRs were created when the
Federal Communications Commission began to license business and commercial 800 MHz two-way radio systems in the late 1970s.
500:
Common Air
Interface (CAI) was accepted at the meeting of the ITU-R (International Telecommunication Union Radiocommunications Sector) held in November
508:, published in February 2017. It is an open, multi-vendor protocol widely adopted in mission-critical applications in Japan, USA and mainland Europe.
659:
275:
system, operated by a service in the VHF, 220, UHF, 700, 800 or 900 MHz bands. Some systems with advanced features are referred to as an
344:
339:
906:
150:
it is very common to be able to assign talkgroups into banks or lock them out, exactly like that of conventional frequencies.
574:
US Patent and
Trademark Office Registration Number 2407576, Serial Number 75400608, registered to Uniden America Corporation.
1146:
562:
1156:
720:
715:
652:
419:
1295:
1209:
1017:
307:
occurs. A major flood or earthquake is likely to generate a level of call traffic that loads the system to capacity.
284:
237:
compatible with trunked systems appeared on the market. One of the first companies to bring these devices to market,
1290:
645:
117:
computer network. Users' radios send data packets to a computer, operating on a dedicated frequency — called a
1126:
969:
431:
advanced features they generally are not suited to mission critical deployments, public access mobile radio (
189:
is a common formula that predicts the optimal number of trunk lines actually needed under normal conditions.
1007:
954:
781:
453:
505:
501:
1176:
1022:
899:
1214:
710:
414:
1239:
1070:
1032:
855:
766:
379:
1264:
1080:
705:
409:
83:
44:
1300:
1224:
1171:
974:
934:
892:
687:
476:
394:
91:
1229:
1234:
949:
944:
792:
459:
134:
8:
1269:
1116:
1002:
939:
837:
632:
364:
613:
Contra Costa County Public Safety Mobile Radio Master Plan, Final Report, June 18, 2002,
133:
A 'talkgroup' is an assigned logical group of users on a trunked radio system. Unlike a
141:, a trunk system uses a number of frequencies allocated to the entire system. Then the
1136:
37:
1121:
700:
548:
Talk groups, scanning, and group calls are defined in, "Section 2: Needs
Summary,"
404:
114:
1254:
1204:
695:
550:
Arizona Phase II Final Report: Statewide Radio
Interoperability Needs Assessment,
525:
432:
399:
322:
Engineering documentation for these systems suggests another evaluation would be
311:
142:
138:
118:
87:
75:
1075:
751:
349:
19:
1284:
1090:
1060:
929:
915:
601:(Phoenix, Arizona: Macro Corporation and The State of Arizona, 2004) pp. 30.)
272:
234:
147:
103:
33:
302:
Some systems experience seasonal peaks. For example, a trunked system in an
1166:
1065:
1055:
860:
850:
845:
798:
494:
Some trunked radio protocols provide additional reliability and security.
384:
374:
369:
1259:
1249:
1244:
303:
41:
637:
741:
71:
1219:
827:
359:
1161:
1106:
1027:
771:
756:
583:
See External link: Federal Communications Commission definition of
530:
515:
269:
186:
1181:
1111:
1012:
959:
865:
761:
736:
448:
443:
389:
884:
627:
1186:
1151:
1037:
984:
979:
964:
471:
238:
79:
200:
746:
520:
354:
241:, trademarked the term 'trunk tracking' on December 5, 1997.
615:(Fairfax, Virginia: Federal Engineering, Inc., 2002) pp. 25.
787:
776:
497:
482:
36:
system that uses a control channel to automatically assign
563:"Conventional and Trunked Radio Systems Comparison Report"
55:, a function automatically handled by a computer system.
552:
Macro Corporation and The State of Arizona, 2004, pp. 16.
435:) type operation or uncoordinated shared user types.
175:
283:). Specialized Mobile Radio is a term defined in US
633:FCC PDF file describing US private radio services.
599:Statewide Radio Interoperability Needs Assessment,
310:Siting of the system affects coverage: the system
244:
1282:
479:, Motorola Capacity Plus, Motorola Connect Plus
172:the talkgroups are stored on the trunked bank.
900:
653:
82:and other municipal services, who all share
628:FCC definition of Specialized Mobile Radio.
468:Icom IDAS Digital trunked Land Mobile Radio
256:
201:Differences from conventional two-way radio
67:to talk together, regardless of frequency.
40:to groups of user radios. In a traditional
907:
893:
660:
646:
97:
667:
212:
113:In essence, a trunked radio system is a
18:
285:Federal Communications Commission (FCC)
1283:
465:Kenwood NEXEDGE Digital trunked radio
888:
641:
485:(integrated Digital Enhanced Network)
293:
153:
74:to provide two-way communication for
489:
108:
13:
621:
176:Comparison with telephone trunking
14:
1312:
1018:Common traffic advisory frequency
914:
277:Enhanced Specialized Mobile Radio
604:
590:
577:
568:
555:
542:
329:
268:) may be an analog or digital
245:Types of trunked radio systems
137:which assigns users a certain
1:
1127:Maritime mobile amateur radio
821:General Electric Mobile Radio
128:
1270:Voting (diversity combining)
1008:Aircraft emergency frequency
955:General Mobile Radio Service
7:
1023:Mandatory frequency airport
425:
166:
10:
1319:
1215:Automatic vehicle location
716:Type II SmartZone OmniLink
420:Type II SmartZone OmniLink
101:
1296:Radio resource management
1240:Dynamic range compression
1195:
1157:Dual-tone multi-frequency
1135:
1099:
1071:Professional mobile radio
1046:
1033:Single Frequency Approach
993:
922:
856:LTR Standard and Passport
836:
820:
811:
729:
686:
679:
675:
511:Other protocols include:
504:and it has been added to
380:LTR Standard and Passport
1265:Radiotelephony procedure
1081:Specialized Mobile Radio
536:
262:Specialized Mobile Radio
257:Specialized Mobile Radio
53:radio traffic controller
45:land mobile radio system
975:Multi-Use Radio Service
324:delivered audio quality
98:Principles of operation
16:Class of a radio system
1047:Land-based commercial
935:Amateur radio repeater
213:Advantages of Trunking
25:
1291:Trunked radio systems
1049:and government mobile
996:(aeronautical mobile)
669:Trunked radio systems
22:
1086:Trunked radio system
950:Public Radio Service
945:Family Radio Service
923:Amateur and hobbyist
59:logical grouping, a
47:a group of users (a
30:trunked radio system
1117:Coast radio station
1003:Air traffic control
940:Citizens band radio
838:Logic Trunked Radio
814:distributed control
365:Logic Trunked Radio
72:government entities
1100:Marine (shipboard)
985:UHF CB (Australia)
680:Central controller
294:Quality of service
154:Fleet maps and IDs
135:conventional radio
38:frequency channels
26:
1278:
1277:
1139:Selective calling
882:
881:
878:
877:
874:
873:
807:
806:
711:Type II SmartZone
490:Advanced systems
415:Type II SmartZone
1308:
1196:System elements
1122:Marine VHF radio
909:
902:
895:
886:
885:
818:
817:
688:Motorola systems
684:
683:
677:
676:
662:
655:
648:
639:
638:
616:
608:
602:
594:
588:
581:
575:
572:
566:
559:
553:
546:
115:packet switching
109:Control channels
76:fire departments
1318:
1317:
1311:
1310:
1309:
1307:
1306:
1305:
1281:
1280:
1279:
1274:
1255:Rayleigh fading
1197:
1191:
1138:
1131:
1095:
1048:
1042:
995:
989:
918:
913:
883:
870:
832:
813:
803:
742:APCO Project 25
737:APCO Project 16
725:
706:Type IIi Hybrid
671:
666:
624:
622:Externals links
619:
609:
605:
595:
591:
582:
578:
573:
569:
560:
556:
547:
543:
539:
526:APCO Project 25
506:Report M.2014-3
492:
449:APCO Project 16
428:
410:Type IIi Hybrid
332:
296:
259:
247:
215:
203:
178:
169:
156:
143:control channel
131:
119:control channel
111:
106:
100:
86:allocated to a
17:
12:
11:
5:
1316:
1315:
1304:
1303:
1301:Radio networks
1298:
1293:
1276:
1275:
1273:
1272:
1267:
1262:
1257:
1252:
1247:
1242:
1237:
1232:
1227:
1222:
1217:
1212:
1207:
1201:
1199:
1198:and principles
1193:
1192:
1190:
1189:
1184:
1179:
1174:
1169:
1164:
1159:
1154:
1149:
1143:
1141:
1133:
1132:
1130:
1129:
1124:
1119:
1114:
1109:
1103:
1101:
1097:
1096:
1094:
1093:
1088:
1083:
1078:
1076:Radio repeater
1073:
1068:
1063:
1058:
1052:
1050:
1044:
1043:
1041:
1040:
1035:
1030:
1025:
1020:
1015:
1010:
1005:
999:
997:
991:
990:
988:
987:
982:
977:
972:
967:
962:
957:
952:
947:
942:
937:
932:
926:
924:
920:
919:
912:
911:
904:
897:
889:
880:
879:
876:
875:
872:
871:
869:
868:
863:
858:
853:
848:
842:
840:
834:
833:
831:
830:
824:
822:
815:
809:
808:
805:
804:
802:
801:
796:
790:
785:
779:
774:
769:
764:
759:
754:
752:EDACS Provoice
749:
744:
739:
733:
731:
727:
726:
724:
723:
718:
713:
708:
703:
698:
692:
690:
681:
673:
672:
665:
664:
657:
650:
642:
636:
635:
630:
623:
620:
618:
617:
603:
589:
576:
567:
554:
540:
538:
535:
534:
533:
528:
523:
518:
491:
488:
487:
486:
480:
474:
469:
466:
463:
457:
451:
446:
444:OpenSky System
427:
424:
423:
422:
417:
412:
407:
402:
397:
392:
387:
382:
377:
372:
367:
362:
357:
352:
350:EDACS Provoice
347:
342:
331:
328:
295:
292:
258:
255:
246:
243:
235:radio scanners
214:
211:
202:
199:
177:
174:
168:
165:
155:
152:
130:
127:
110:
107:
99:
96:
15:
9:
6:
4:
3:
2:
1314:
1313:
1302:
1299:
1297:
1294:
1292:
1289:
1288:
1286:
1271:
1268:
1266:
1263:
1261:
1258:
1256:
1253:
1251:
1248:
1246:
1243:
1241:
1238:
1236:
1233:
1231:
1228:
1226:
1223:
1221:
1218:
1216:
1213:
1211:
1208:
1206:
1203:
1202:
1200:
1194:
1188:
1185:
1183:
1180:
1178:
1175:
1173:
1170:
1168:
1165:
1163:
1160:
1158:
1155:
1153:
1150:
1148:
1145:
1144:
1142:
1140:
1134:
1128:
1125:
1123:
1120:
1118:
1115:
1113:
1110:
1108:
1105:
1104:
1102:
1098:
1092:
1091:Walkie-talkie
1089:
1087:
1084:
1082:
1079:
1077:
1074:
1072:
1069:
1067:
1064:
1062:
1061:Business band
1059:
1057:
1054:
1053:
1051:
1045:
1039:
1036:
1034:
1031:
1029:
1026:
1024:
1021:
1019:
1016:
1014:
1011:
1009:
1006:
1004:
1001:
1000:
998:
992:
986:
983:
981:
978:
976:
973:
971:
968:
966:
963:
961:
958:
956:
953:
951:
948:
946:
943:
941:
938:
936:
933:
931:
930:Amateur radio
928:
927:
925:
921:
917:
916:Two-way radio
910:
905:
903:
898:
896:
891:
890:
887:
867:
864:
862:
859:
857:
854:
852:
849:
847:
844:
843:
841:
839:
835:
829:
826:
825:
823:
819:
816:
810:
800:
797:
794:
791:
789:
786:
783:
780:
778:
775:
773:
770:
768:
765:
763:
760:
758:
755:
753:
750:
748:
745:
743:
740:
738:
735:
734:
732:
728:
722:
719:
717:
714:
712:
709:
707:
704:
702:
699:
697:
694:
693:
691:
689:
685:
682:
678:
674:
670:
663:
658:
656:
651:
649:
644:
643:
640:
634:
631:
629:
626:
625:
614:
607:
600:
593:
586:
580:
571:
564:
561:The document
558:
551:
545:
541:
532:
529:
527:
524:
522:
519:
517:
514:
513:
512:
509:
507:
503:
499:
495:
484:
481:
478:
475:
473:
470:
467:
464:
461:
458:
455:
452:
450:
447:
445:
442:
441:
440:
436:
434:
421:
418:
416:
413:
411:
408:
406:
403:
401:
398:
396:
393:
391:
388:
386:
383:
381:
378:
376:
373:
371:
368:
366:
363:
361:
358:
356:
353:
351:
348:
346:
343:
341:
338:
337:
336:
327:
325:
320:
316:
313:
308:
305:
300:
291:
288:
286:
282:
278:
274:
273:two-way radio
271:
267:
263:
254:
251:
242:
240:
236:
231:
227:
223:
219:
210:
206:
198:
194:
190:
188:
182:
173:
164:
160:
151:
149:
148:radio scanner
144:
140:
136:
126:
122:
120:
116:
105:
104:Erlang (unit)
95:
93:
89:
85:
81:
77:
73:
68:
66:
62:
56:
54:
50:
46:
43:
39:
35:
34:two-way radio
31:
21:
1177:Quik-Call II
1167:Push-to-talk
1137:Signaling /
1085:
1066:Mobile radio
1056:Base station
861:LTR MultiNet
851:LTR Passport
846:LTR Standard
812:Scan-based /
668:
612:
606:
598:
592:
584:
579:
570:
557:
549:
544:
510:
496:
493:
437:
429:
385:LTR MultiNet
375:LTR Passport
370:LTR Standard
333:
323:
321:
317:
309:
304:agricultural
301:
297:
289:
280:
276:
265:
261:
260:
252:
248:
232:
228:
224:
220:
216:
207:
204:
195:
191:
183:
179:
170:
161:
157:
132:
123:
112:
69:
64:
60:
57:
52:
48:
29:
27:
1260:Tone remote
1250:Link budget
1245:Fade margin
1172:Quik-Call I
345:Ericsson GE
330:Entry-level
42:half-duplex
1285:Categories
970:Mobile rig
129:Talkgroups
102:See also:
1230:DC remote
1220:Call sign
994:Aviation
828:GE Marc V
360:GE Mark V
340:SmarTrunk
233:In 1997,
139:frequency
65:talkgroup
61:talkgroup
49:talkgroup
1235:Dispatch
1162:MDC-1200
1107:2182 kHz
1028:MULTICOM
795:Tier III
772:TETRAPOL
757:MPT-1327
531:TETRAPOL
516:MPT-1327
477:Motorola
462:Tier III
426:Standard
395:Motorola
312:antennas
187:Erlang-B
167:Scanning
84:spectrum
1205:Antenna
1182:Selcall
1112:500 kHz
1013:Airband
960:KDR 444
866:LTR-Net
762:OpenSky
701:Type II
405:Type II
390:LTR-Net
270:trunked
24:system.
1187:SELCAL
1152:D-STAR
1038:UNICOM
980:PMR446
965:LPD433
784:Mode 3
696:Type I
587:below.
472:Hytera
456:Mode 3
400:Type I
335:only.
239:Uniden
92:county
80:police
1147:CTCSS
767:TETRA
747:EDACS
730:Other
537:Notes
521:TETRA
355:EDACS
32:is a
1210:APRS
788:NXDN
782:dPMR
777:GoTa
721:iDEN
502:2016
498:NXDN
483:iDEN
454:dPMR
433:PAMR
281:ESMR
88:city
1225:CAD
799:PDT
793:DMR
585:SMR
460:DMR
266:SMR
1287::
90:,
78:,
28:A
908:e
901:t
894:v
661:e
654:t
647:v
279:(
264:(
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
