|
Trunked Radio Systems
A Trunked Radio System (TRS) 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 ... [...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 other companies such as Midland and Realistic, which rebranded the equipment under their own labels. Uniden also marketed CB Radios in the UK under the Uniden and Uniace brands during the early '80s. 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 BearCat brand). In Europe, it became successful in the telecommunications market with its introduction of 900 MHz cordless telephones. As Uniden continued to grow and extend its international operations, Uniden Australia and Uniden New Ze ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LTR Standard And Passport
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. LTR systems are limited to 20 channels (repeaters) per site and each site stands alone (not linked). is 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. Some ... 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 subscr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LTR Passport
PassPort is a type of LTR Trunked radio system A Trunked Radio System (TRS) 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'') w ... 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 limitation 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 e ... [...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. Each system site can have any number of radio channels from 1 through a maximum of 20. Each channel is made up of one channel controller connected to one radio repeater operating on one frequency. One controller is assigned as the master or system controller and all the other controllers report to it via a trunking data buss. This connection allows all the repeaters at a site to operate as one LTR system. 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.http://www.gbppr.net/scanner/LTR-FAQ.pdf 4.4 DATA MESSAGE FORMAT * "A" is the ar ... [...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. LTR systems are limited to 20 channels (repeaters) per site and each site stands alone (not linked). is 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. Some ... 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 subs ... [...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. Radi ... [...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. The rights were eventually bought by Harris Corporation, which eventually stopped manufacturing these devices in 2012, and ended all service in 2017. 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 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-tolerant. This provided substantial hardware reductions, and the re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EDACS Provoice
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. The rights were eventually bought by Harris Corporation, which eventually stopped manufacturing these devices in 2012, and ended all service in 2017. 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 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-tolerant. This provided substantial hardware reductions, and the req ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ericsson GE
(), commonly known as Ericsson (), is a Swedish multinational networking and telecommunications company headquartered in Stockholm, Sweden. Ericsson has been a major contributor to the development of the telecommunications industry and is one of the leaders in 5G. Ericsson has over 57,000 granted patents and it is the inventor of Bluetooth technology. The company sells infrastructure, software, and services in information and communications technology for telecommunications service providers and enterprises, including, among others, cellular 4G and 5G equipment, and Internet Protocol (IP) and optical transport systems. The company employs around 100,000 people and operates in more than 180 countries. The company is listed on the Nasdaq Stockholm under the ticker symbols ERIC.A and ERIC.B and on the American Nasdaq under the ticker symbol ERIC. The company was founded in 1876 by Lars Magnus Ericsson and is jointly controlled by the Wallenberg family through its holding comp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antenna (radio)
In radio-frequency engineering, an antenna (American English) or aerial (British English) is an electronic device that converts an alternating current, alternating electric current into radio waves (transmitting), or radio waves into an electric current (receiving). It is the interface between radio waves Radio propagation, propagating through space and electric currents moving in metal Electrical conductor, conductors, used with a transmitter or receiver (radio), receiver. In transmission (telecommunications), transmission, a radio transmitter supplies an electric current to the antenna's Terminal (electronics), terminals, and the antenna radiates the energy from the current as electromagnetic radiation, electromagnetic waves (radio waves). In receiver (radio), reception, an antenna intercepts some of the power of a radio wave in order to produce an electric current at its terminals, that is applied to a receiver to be amplifier, amplified. Antennas are essential components ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
