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Trunked Radio System
A trunked radio system is a two-way radio system that uses a control channel to automatically assign frequency channels to groups of user radios. In a traditional half-duplex land mobile radio system a group of users (a ''talkgroup'') 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'. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Uniden
() is a Japanese company in the wireless communication industry. History Uniden was established on February 7, 1966, by its founder Hidero Fujimoto as "Uni Electronics Corp". Uniden became a well-known brand in the 1970s by manufacturing and marketing millions of citizens band radios (CB), under the Uniden brand as well as many for popular private brand labels such as Clegg (amateur transceivers), Cobra, Craig, Fanon-Courier, Midland (only certain clone models, originals were made by Cybernet), President, Teaberry, Stalker, Super Star, Teledyne-Olson, Pearce Simpson, Realistic, Regency, Robyn and many European brands such as Zodiac, Stabo and Inno-Hit. Uniden also marketed CB Radios in the UK under the Uniden and Uniace brands during the late 1970s. During the 1980s, Uniden grew to become the world's largest manufacturer of cordless telephones in addition to television satellite equipment, mobile radios, advanced marine electronics and radio scanners (the latter under brand ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Motorola Type I
Motorola Type I Is the original type of Motorola's Trunked radio system A trunked radio system is a two-way radio system that uses a control channel to automatically assign frequency channels to groups of user radios. In a traditional half-duplex land mobile radio system a group of users (a ''talkgroup'') with mobi ...; it is based on Fleets and Subfleets. Each system had a certain number of Fleets assigned, and then each Fleet had a certain number of Subfleets and radio IDs. The distribution of Fleets and Subfleets on a Type I system is determined by the system Fleetmap. Motorola Type I systems are not scalable because they limit the amount of IDs any fleet or subfleet can support. Each Type I ID appears as a three or four digit number, followed by a hyphen, followed by a one or two digit number (example 200-14). The term "Privacy Plus" refers to a Type I system. Privacy Plus systems are normally older public safety systems and SMRs. {{Trunked radio systems Trunked radi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Motorola Trunked Radio
Motorola Trunked Radio is a trunked radio system developed by Motorola. Types * Type I * Type II * Type IIi Hybrid * Type II SmartZone * Type II SmartZone OmniLink * Type II VOC Motorola Type I and Type II systems achieve the same thing in a slightly different way. One important distinction between these systems is the amount of data transmitted by each radio when the operator pushes the PTT button. A Type I system transmits the radio's ID, its fleet information, and the subfleet information. A Type II system only transmits the radio's ID. What’s the difference? In Type I systems, each radio in the trunk group individually transmits its own affiliation. In Type II systems the trunk system maintains a database that determines each radio's affiliation. Another difference between the systems is that Type I systems are arranged in a fleet-subfleet hierarchy. For example, it is possible for a city using a Type I system to designate four fleets, each with eight subfleets. The p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LTR MultiNet
LTR MultiNet Systems are APCO-16 compliant LTR Trunked Radio Systems and thus are mostly found in use as public safety systems. LTR MultiNet systems usually have one or more "status channels" that act like a control channel in a Motorola or EDACS system, however these channels can also carry voice transmissions simultaneously. APCO 16 compliance Some trunked systems queue calls if a user's attempt to transmit gets a busy signal. In other words, if someone presses their push-to-talk button and all trunked radio system channels are busy, some systems will wait-list users in the same order as their busy signals occur. When a channel becomes available, the system notifies the user. There is disagreement about MultiNet's ability to queue calls when all channels are busy. Usually, the control channel is the path allowing wait-listed users to get in line. One publication says MultiNet communicates using low baud rate data multiplexed under voice if all channels are busy. One report say ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LTR Standard And Passport
LTR Standard and Passport systems are hybrid Trunked Radio Systems that have some LTR Standard talkgroups and some LTR Passport PassPort is a type of LTR Trunked radio system designed by Trident Micro Systems, which consists of multiple radio repeater sites linked together to form a wide-area radio dispatch network. Purpose Radio signals have a limitations due to distance ... talkgroups. Logic Trunked Radio {{radio-comm-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LTR Passport
PassPort is a type of LTR Trunked radio system designed by Trident Micro Systems, which consists of multiple radio repeater sites linked together to form a wide-area radio dispatch network. Purpose Radio signals have a limitations due to distance and terrain. If two radios are far apart, or there is a mountain in the way, they will not be able to communicate. To alleviate this, radio repeaters are installed on mountaintops to repeat the signal from one radio to another, or group of others. This is a standard repeater site. The signal is received by the repeater from the originating radio and re-broadcast so the receiving radio(s) can receive the radio signal. A repeater site gives approximately a 50-mile radius of coverage. Trunk ed radio is a method of using a bank of channels (frequencies) to repeat for multiple "Talk Groups" or fleet of radios. Many Talk Groups can share the channels, without hearing each other's conversation. A Passport system combines both of these technologi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LTR Standard
Within radio technology, LTR (Logic Trunked Radio) Standard systems have no dedicated control channel. All control data is sent as subaudible data along with voice transmissions. Systems can have any number of channels from 1 through a maximum of 20. Each channel in the system is assigned a unique number (01 through 20) and these need not be sequentially assigned. Each subscriber radio must be programmed with all channels in the system in proper logical channel order (the same requirement as EDACS systems). LTR Standard Talkgroups are written in the format A-HH-GGG. * "A" is the area code and is either 0 or 1. The area code is the same for all Talkgroups in a given system and is arbitrarily chosen by the system operator; the most common use is to simply distinguish between Talkgroups on multiple systems. * "HH" is the home repeater number and has twenty possible values, 01 through 20. Talkgroups usually use their home repeater by default, unless the repeater is already in use ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Logic Trunked Radio
Logic Trunked Radio (LTR) is a radio system developed in the late 1970s by the E. F. Johnson Company. LTR is distinguished from some other common trunked radio systems in that it does not have a dedicated control channel. Each repeater In telecommunications, a repeater is an electronic device that receives a signal and retransmits it. Repeaters are used to extend transmissions so that the signal can cover longer distances or be received on the other side of an obstruction. Som ... has its own controller and all of these controllers are coordinated together. Even though each controller monitors its own channel, one of the channel controllers is assigned to be a master and all the other controllers report to it. Typically on LTR systems, each of these controllers periodically sends out a data burst (approximately every 10 seconds on LTR Standard systems) so that the subscriber units know that the system is there. The idle data burst can be turned off if desired by the system ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GE Mark V
GE Marc V is a historic U.S. format or protocol of trunked, two-way radio introduced by General Electric Mobile Radio in the early 1980s. This equipment was also sold in Australia. The product name looks and sounds similar to ''GE-Mark V'', a turbine controller made by General Electric. GE developed the EDACS radio system based on its success with Marc V. Details These radios are seen as obsolete and there is only one known instance of this system operating in the U.S. today (Grant County, Oklahoma). The general category of this kind of trunked system is called, "Scan-based trunking." In the U.S. and Australia, these systems used analog FM, operated in the 806-869 MHz band, and were primarily used for commercial, non-public-safety trunking. Some earlier systems offered half-duplex, (push-to-talk) telephone interconnect and later versions also offered full duplex telephone interconnect. This feature was popular before the rollout of analog cellular telephones. Radio mod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EDACS
The Enhanced Digital Access Communication System (EDACS) is a radio communications protocol and product family invented in the General Electric Corporation in the mid 1980s. History A young designer, Jeff Childress, created an autonomous radio base-station controller, known as the GETC (General Electric Trunking Card). The GETC was a general-purpose controller with input/output optimized for radio system applications. Childress and the team demonstrated that a smart controller could be adapted to a variety of applications, but his interest was really in fault tolerance. The competition dealt with fault tolerance by means of the "brute force and ignorance" approach, deploying double the hardware for their controllers, and interconnecting them with massive and problematic relay banks . The EDACS system architecture supported large communications footprints. By making the GETC's "trunk" among themselves, one GETC per channel, the system was designed to be inherently fault-t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |