User's Manual

20-523 Owner’s Manual
Page 30
When an ID code is received, the ID list for the bank is searched, and if found, the text name stored for the ID
appears. If not found, scanning resumes immediately unless the bank is in open trunking mode.
Note: There might be more than one talk group transmitting at a time in some Motorola trunking systems. If
you set the scanner to manually tune in Motorola trunking mode, you will hear the talk group on that channel,
but the display will alternate between all active IDs.
Trunking group frequencies are included in the supplied Police Call Trunking Guide. Frequency fleet map
and talk group information is also widely available on the Internet, at www.trunkscanner.com for example.
UNDERSTANDING TRUNKING
In the past, groups that transmit frequently, such as police departments, could transmit on only a few
frequencies. This resulted in heavy traffic and often required 2-way radio users to wait for a specific
frequency to clear before transmitting. Trunked systems allow more groups of 2-way radio users to use fewer
frequencies. Instead of selecting a specific frequency to transmit on, a trunked system chooses one of
several frequencies when the 2-way radio user transmits. The system automatically transmits the call on that
frequency, and also sends a code that identifies that 2-way radio user’s transmission on a control channel.
This scanner lets you easily hear both the call and response transmissions for that 2-way radio user and
therefore follow the conversation. For EDACS and Motorola (above 406 MHz range), the scanner monitors
the control channel between each transmission to identify talk groups.
SETTING SQUELCH FOR THE TRUNKING MODE
Your scanner automatically mutes the audio during trunk scanning when it decodes control channel data.
However, we recommend you turn SQUELCH clockwise and leave it set to a point just after the hissing
sound stops. This lets the scanner quickly acquire the data channel.
PROGRAMMING TRUNKING FREQUENCIES
You program trunking frequencies just like non-trunked frequencies, except that you must store the
appropriate mode (MO or ED) with each frequency.
Notes:
• You can store only one trunked EDACS and Motorola channel in a bank. You can, however, mix
conventional channels in a bank.
• If you are programming trunked frequencies for Motorola Type I and hybrid systems, you must first program
the fleet map (see “Programming Fleet Maps” on Page XX).
Follow these steps to program trunked frequencies.
1. Press PGM and select the bank, then press TRUNK to enter the ID program mode.
2. Repeatedly press MODE to select MO for Motorola, or ED for the EDACS (GE/Ericsson) system to scan.
This sets the talk group ID decoding method to be used for the bank.