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SMARTNET/SMARTZONE/P25 TRUNKED FEATURES
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access permissions to steer certain talkgroups to
particular sites. For example, a police department may
be allowed to use only Site 1, and a public works
department may be allowed to use only Site 2.
particular sites. For example, a police department may
be allowed to use only Site 1, and a public works
department may be allowed to use only Site 2.
The problem with this operation is that every time
a different talk group is selected, the access permission
may be different and a different site may need to be
accessed. This could result, in a worst case, in a delay
of up to 30 seconds in finding a new site. This could
occur if there are no valid sites for the new talk group
in the dynamic site list.
may be different and a different site may need to be
accessed. This could result, in a worst case, in a delay
of up to 30 seconds in finding a new site. This could
occur if there are no valid sites for the new talk group
in the dynamic site list.
P25 Wide Area Scan
A feature called Wide Area Scan can be
programmed to minimize the problem just outlined.
This feature is programmed on the Talk Group list
screen selected on the P25 System screen. When Wide
Area Scan is selected, talk group site preferences are
no longer available. However, System Site Preference
lists can still be used. The Wide Area Scan feature
functions as follows:
This feature is programmed on the Talk Group list
screen selected on the P25 System screen. When Wide
Area Scan is selected, talk group site preferences are
no longer available. However, System Site Preference
lists can still be used. The Wide Area Scan feature
functions as follows:
1. Assume TG1 is selected. If it is the first time this
talk group is selected, normal searching for a control
channel occurs according to the hunt methods
previously described.
channel occurs according to the hunt methods
previously described.
2. When another talk group is selected, the active valid
site for TG1 is stored in EEPROM memory.
3. The next time TG1 is selected, the following proce-
dure is performed before performing the normal
hunt methods previously described.
hunt methods previously described.
a. The last valid site ID and its receive and transmit
channel numbers are loaded from EEPROM
memory.
memory.
b. The dynamic site list is checked to see if any
newer receive/transmit channel information is
available for the last site ID.
available for the last site ID.
c. The best receive/transmit information is used and
the radio checks to see if this control channel is
available.
available.
The result of the preceding operation is that the
radio has a reasonable chance of finding a valid site,
usually on the first try. This greatly reduces access
time, even on systems which have highly restricted
talk group based access.
usually on the first try. This greatly reduces access
time, even on systems which have highly restricted
talk group based access.