E.F. Johnson Viking VM600 Series, Руководство по эксплуатации

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7-22 Viking VM600 Mobile Radio Operating Manual
SMARTNET / SmartZone / P25 Trunked Features
The problem with this operation is that every time a different talkgroup 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 talkgroup in the dynamic site list.
7.13.10 P25 Wide Area Scan
This feature is intended to enhance roaming performance, especially when system level
steering through radio or talkgroup permissions is used.
To use system channel resources more efficiently, some system operators are using system
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.
A Wide Area Scan can be programmed to minimize the problem just outlined. This feature
is programmed on the Talkgroup list screen selected on the P25 System screen. When
Wide Area Scan is selected, talkgroup 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 talkgroup is selected, normal
searching for a control channel occurs according to the hunt methods previously
described.
2
When another talkgroup is selected, the active valid site for TG1 is stored in EEPROM
memory.
3
The next time TG1 is selected, the following procedure is performed before performing
the normal hunt methods previously described.
a
The last valid site ID and its receive and transmit channel numbers are loaded from
EEPROM memory.
b
The dynamic site list is checked to see if any newer receive/transmit channel
information is 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.
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 talkgroup based access.
With this option enabled on a talkgroup, as the talkgroup affiliates with a site that site is
saved if the mobile is changed to a new talkgroup. When the radio moves back to the Wide
Area Scan talkgroup, it will attempt to affiliate on the saved site before looking for a new
site.
Draft 4/29/2014