Tyco Electronics MM23772 Portable Radio User Manual


 
MM23772, Rev. B
67
8.21 SCANNING TRUNKED SYSTEMS
The radio can be programmed with the following System Scan features. These features are automatically
enabled when the radio is powered ON. A key or menu option is also defined to allow the System Scan
features to be toggled during radio operation. The System Scan state will be maintained through system
changes but will default to ON when the radio is powered ON.
Enable/Disable via Menu Selection:
Press and then use the or buttons to scroll through the selections until SYS SCAN is displayed.
Then press to toggle the System Scan state. The SYSC ON or SYSC OFF display message is
displayed for two seconds to show the new state.
Enable/Disable via Pre-Programmed Keypad Key:
Press the key pre-programmed to toggle System Scan and the SYSC ON or SYSC OFF display message
is displayed for two seconds to show the new state.
8.21.1 Wide Area System Scanning
The P7200 series radio can be programmed for Wide Area System Scan operation for roaming across
mobile systems. Upon the loss of the currently selected system's control channel, radios can be
programmed to automatically scan the control channels of other systems. If a new control channel is
found, the radio will switch to the new system and sound an alert tone.
8.21.2 Priority System Scan
The radio can also be programmed for Priority System Scan. The priority system is the desired or
preferred system. While receiving the control channel of the selected system, the radio will periodically
leave the selected system and search for the control channel of the priority system. This is done at a
programmable rate defined by the value in the Priority Scan Time control (unless the ProScan
algorithm
is enabled, as explained in the following sections). This priority scan timer is reset each time the PTT
button is pressed or when the call is received. If the priority system control channel is found, (or meets the
predefined criteria <ProScan>), the radio will automatically switch to the priority system.
8.21.2.1 Enabling the Wide Area System Scan Function
If the radio cannot find the control channel of the selected system and begins to wide area system scan,
the radio will only scan for the priority system control channel if the priority system is in the wide area
scan list.
8.21.2.2 When ProScan is Enabled
The radio monitors the priority system and will switch to the priority system if the criteria defined by the
controls in the ProScan Options dialog box are met. If ProScan is enabled, the rate at which the radio will
scan for the priority system is defined by the System Sample Time control, located in the ProScan
Options dialog box. See Section
8.21.3 for more information on ProScan
8.21.3 ProScan
The radio may be programmed for ProScan system scan operation for multi-site applications depending
on the version of radio flash code. ProScan is an improved multi-site system scanning algorithm designed
to replace ProSound
scanning. ProScan provides the radio with the ability to select a new system for the
radio to communicate on, when the selected system drops below a predefined level. This is accomplished
by enabling each radio to analyze the signal quality of its current control channel and compares it with the