Quote:
Originally Posted by 89liam146
what is trunking?
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The object of trunking is to allow many users to share a relatively few frequencies.
A trunking system is controlled by a computer. Information is sent and received from the radios to the computer on a control channel, sometimes called a data channel. It sounds like a strong buzz. When a scanner is trunking properly, you will not hear the control channel.
A large Motorola system (the most common) can have up to 28 freqs., 4 of which may be used as control channels. The control channel may be changed once a day or as often as the programmer decides. Newer scanners need only the control channel to track the entire system, but it is best to put in all the freqs. in case they change the CC some day. Some systems seldom change the control channels.
Each group of users (Fire, Police, etc.) are assigned identifiers called TALK GROUPS or IDs. In a Motorola Type II system, the most common type, TGs are usually in 32 number steps from 16 to 65536; 16, 48, 80 --- 4656, 4688, 4720 --- 28944, 28976, 29008, etc. System radios have up to 160 TGs programmed into them.
When a mic is keyed, data is sent to the computer. The computer chooses an unused freq. and sends that data to all the radios set to the TG of the originating unit. This all happens in a fraction of a second and it happens EVERY time a mic is keyed.
EXAMPLE:
Fire Dispatch calling Engine 4 (TG 4528 on 856.7125)
Engine 4 answering Dispatch (TG 4528 on 867.2625)
Respond to 73 Elm Street for a grass fire (TG 4528 on 866.9625)
Engine 4 responding to 73 Elm Street (TG 4528 on 858.4375)
If you have entered TG 4528 into your scanner, it will decode the control channel data and automatically change frequencies to follow the conversation on TG 4528.
what is trunking?
Linear Mode
