Logic Trunked Radio (LTR) is a
radio
Radio is the technology of signaling and communicating using radio waves. Radio waves are electromagnetic waves of frequency between 30 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a transm ...
system developed in the late 1970s by the
E. F. Johnson Company
EF Johnson Technologies, Inc. is a two-way radio manufacturer founded by its namesake, Edgar. Frederick Johnson, in Waseca, Minnesota, United States in 1923. Today it is a wholly owned subsidiary of JVCKenwood of Yokohama, Japan.
EF Johnson Techn ...
.
LTR is distinguished from some other common
trunked radio systems in that it does not have a dedicated
control channel
In radio communication, a control channel is a central channel that controls other constituent radios by handling data streams. It is most often used in the context of a trunked radio system, where the control channel sends various data which coo ...
. 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
In telecommunication, a burst transmission or data burst is the broadcast of a relatively high-bandwidth transmission over a short period.
Burst transmission can be intentional, broadcasting a compressed message at a very high data signaling rate ...
(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 operator. Some systems will broadcast idle data bursts only on channels used as home channels and not on those used for "overflow" conversations. To a listener, the idle data burst will sound like a short blip of static like someone keyed up and unkeyed a radio within about 1/2 second. This data burst is not sent at the same time by all the channels but happen randomly throughout all the system channels.
References
External links
Logic Trunked System article from 'Monitoring Times'*
E.F. Johnson Company website
{{Trunked radio systems
Radio electronics
Radio resource management
Radio networks