User's Manual

20-523 Owner’s Manual
Page 12
In all major metropolitan areas of the United States, every available radio channels is assigned to more than
one user. Public safety radio systems on the same frequency are usually set up at a distance of 40 miles
apart, or more. This means that you may hear transmissions from a distant system when your local system is
not transmitting.
Open and Closed Modes
You can set your scanner to change the way it receives signals. These settings, called open mode and
closed mode, affect how the scanner receives signals from communications systems that use some type of
closed squelch (such as MOT, and ED systems).
You can set each of the scanner’s channel storage ID banks to open or closed mode.
In open mode, the scanner scans signals transmitted in all systems. In closed mode, the scanner scans
signals transmitted only under the following conditions:
. When the signals are in the FM mode.
. When the signals are in the MO, or ED mode and the signal’s ID code matches the programmed ID code.
You can also select the users or talk groups you want the scanner to receive in closed mode.
When you set a channel storage bank to open mode, + (open) appears under the bank’s number while
scanning. When you set a channel storage bank to closed mode, - (closed) appears under the channel
storage bank’s number while scanning. Or, OPEN or CLOSED appears while the scanner is in manual mode
or while the scanner is receiving a signal during scanning.
See “Changing the Open/Closed Mode” on Page XX for more information about setting the open and closed
modes.
AM Mode
This sets the scanner to receive transmissions using amplitude modulation (AM). AM is used for aircraft,
military, some amateur radio, and some government transmissions. When the scanner receives a
transmission on a channel set to the AM mode, it always stops on the transmission.
FM Mode
This sets the scanner to receive transmissions using frequency modulation (FM). FM is used for most public
safety transmissions, as well as broadcast, business, and amateur radio transmissions. When the scanner
receives a transmission on a channel set to the FM mode, it always stops on the transmission.
Motorola Mode
You can set your scanner so it decodes the talk group IDs used with Motorola trunking systems. This setting
is called the Motorola mode.