8M083X25 R14
APX Series P25 Interface
DVRS Installation & Programming Guide
–
PART I
January 2019
Page 23 of 153
Identifying Your DVRS Model
Frequency Band of Operation
Depending on the frequency band of operation of the APX Mobile Subscriber Unit (MSU)
and DVR, the DVRS models are classified as follows:
•
In-Band
– when the MSU and DVR operate in the same frequency band.
•
Cross-Band
– when the MSU and DVR operate in two different frequency bands.
Cross-Band
Cross-Band DVRS models do not include any filters on the MSU side since the MSU and
DVR are not intended to simultaneously operate in the same frequency band. In single
band MSU configurations the MSU and DVR operate in different frequency bands.
In dual band MSU configuration either the MSU & DVR operate in 3 different frequency
bands or one of the MSU frequency bands is locked out when DVR operation is enabled
as shown on
Figure 1 Cross-Band Full Duplex & Simplex Capable DVRS - Conceptual Diagram
The Cross-Band DVRS typically includes a duplexer which can accommodate full duplex
and simplex DVR operation as shown on
Figure 1.
The cross-band duplexer however has
a limited pass-band window and is tuned to the DVR frequencies provided on the purchase
order.
APX8500 may require the interface kit. Please refer to the DVR/VRX1000 Ordering Guide.
As an option, a cross-band DVRS can be configured for simplex
only
operation as shown
on
Figure 2
. In this case the DVRS does not utilize any filters.
