8M083X25 R14
APX Series P25 Interface
DVRS Installation & Programming Guide
–
PART II
January 2019
Page 94 of 153
Band Locking
When both the MSU and DVR are configured to operate in the same frequency band, the
DVRS requires a special set of filters including an in-band filter placed at the MSU antenna
port. The special in-band filters are required in order to prevent interference when the DVR
and MSU are activated at the same time. When the in-
band filter is not present (‘MSU RF
Bypass switch’ in the Tweaker Hardware setup screen is unchecked), the Band Lock
feature is enabled by default and the Tweaker prevents DVR operation on MSU channels
that are explicitly using the same frequency band as the DVR. On MSU channels where
the frequency band is not explicitly known such as in multi-site Trunking systems, the MSU
will be prevented from using frequencies in the same band while the DVR is active (i.e. in
SYSTEM or LOCAL mode). In this case the MSU will no longer allow roaming to sites
using the locked-out band. If the MSU is currently on a Trunking site that uses the locked-
out band, the MSU will roam to another site. If no other sites are available, the MSU will
become ‘Out Of Range’. When the DVR is inactive (OFF mode), the MSU frequency band
is unlocked.
If Band Locking is disabled in the Tweaker, the MSU is allowed to roam to any site
regardless of the frequency band. A typical in-band application that may require Band
Locking to be disabled is the Fixed DVRS application when the MSU and DVR antennas
are mounted in such way as to provide minimum 70db of isolation and in-band filtering is
not required.
For MSU conventional channels where the band is known and fixed, the DVR restricts
access to channels using the locked-out frequency band.
If Band locking is enabled in the DVR and SCAN is enabled in the MSU, the MSU will skip
over any channels in the scan list that are configured to operate in the same frequency
band as the DVR.
In Car Monitor (ICM)
The ICM feature allows the MSU to monitor PSU voice traffic and is configurable in the
MSU codeplug as follows:
•
ICM is enabled / disabled globally in the MSU via the ‘ICM Allowed’ field
•
If ‘ICM Allowed’ is programmed in the MSU then ICM operation is further
configured on a per MSU channel basis via the ‘ICM Allowed’ codeplug field.
•
ICM functionality is further configured to be triggered by either HUB on / off
transitions OR via Menu Item / Button on the MSU control head or keypad Mic.
When ICM functionality is configured to be triggered via HUB on/off then ‘ICM Selected’
operation takes place when the MSU microphone is placed on HUB, ‘ICM All’ operation
will take place when the MSU microphone is taken off HUB.
For details on how to program the ICM functionality and options in the MSU, please refer
to the corresponding Motorola documentation.
When the MSU is operating on a Trunking FNE with ICM enabled the following
configurations are available:
•
‘ICM Selected’ – the MSU speaker unmutes to PSU audio matching its selected
TG ID (digital DVR channel) or all qualified analog PSU audio (analog DVR
channel).
