Trunking system means a method to bring about a sharing of limited radio frequencies among a large group of users at the same time. Since the radio frequencies have to be shared, the radio needs a path or track to convey the messages. A main controlling radio organizes a group of people to use a selected frequency. The system works with many groups at a given time. Instead of allotting a radio frequency to an individual, the trunking system gets a user group to share a frequency. In order to enhance the clarity of voice and to get a good coverage the system uses repeaters.
The repeater receives the transmission through a frequency (A) and redirects the received transmission through another frequency. (B) There are two types of repeaters. Wired and wireless. Wireless repeater is a tool to enhance the frequencies sent through various routes. The wireless repeater creates a point for the sound wave to be sent back to main path in a magnified strength. Thus one can say that a wireless repeater gives the main route an added support. Here the thought of portable radio comes to one's mind.
A Portable digital Radio is an improvised version of a portable radio. This changes the radio frequencies into a numeric version. These radios are useful to person, when he is on the move. Business groups use the portable digital radioto communicate with the staffs who are working at different locations. Another mobile radio that is useful in the business world I is the DMR.
DMR (Digital Mobile Radio) is a procedure of using the numeric code to modify the diction and to send it as frequencies. DMR is an improved version of a PMR solution.