frequency so another talkgroup can use it.
Sharing of the available public service frequencies, or trunking, allows cities, counties, or other agencies to accommodate hundreds of users with relatively few frequencies. Following a conversation on a trunked system using a scanner is difficult, if not impossible. Because when there's a short break during the conversation you're monitoring, it’s possible that the talkgroup will be assigned to a completely different frequency in the trunked system. This type of scanning is difficult and frustrating.
TrunkTracker III changes this! Not only does your new BC250D scan channels like a conventional scanner, it actually follows the users of a trunked radio system. Once you know a talkgroups ID, you won’t miss any of the action.
If you're a new scanner enthusiast, you may want to read the first part of this manual and use your scanner in conventional mode before you begin trunk tracking. Understanding scanning fundamentals and its terminology will make trunk tracking much easier. A glossary of other commonly used terms is provided in the back. (Refer to the "Glossary of Terms" section.) But if you're already an experienced scanner operator, you may want to skip to Programming and Receiving Digital and Trunked Systems on page 49.
What is APCO Project 25 Digital
Communications?
APCO Project 25 is a modulation process where voice communications are converted into digital communications. This conversion is similar to the technology used with digital mobile phones. There are several types of project 25 systems available!
-Conventional – one frequency with digital voice.
-Trunked with analog control channel and digital voice – control channel operates at 3600 baud.
-Mixed Mode – trunked system with an analog control channel alternating/mixing analog and digital voice communications.
-Trunked with digital control channel and digital voice. Control channel operates at 9600 baud. (This type of APCO
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