8M083X25 R14
APX Series P25 Interface
DVRS Installation & Programming Guide
–
PART II
January 2019
Page 97 of 153
Th’
and 3 Heart Beats are missed, the Secondary DVR will start negotiating becoming a
Primary.
IMPORTANT!
The DVR cannot transmit Heart Beats while it is busy repeating.
The ‘Heart Beat’ Interval (3-60 sec) is set by the
‘Heart Beat Interval’
field in the
Primary/Secondary Setup
. The default programmed Heart Beat Interval value is 5
seconds.
When the
‘Enable BL for Voice Communication’
field (
Primary/Secondary
Setup
Screen) is enabled (checked), the DVRS goes through an extra simulcast
prevention check step. Prior to transmitting, a Primary DVR checks for any transmission
(on the DVR Tx frequency) exceeding the programmed
‘Busy LC Th’
(see
Repeater
Channel Setup
Menu). If no such RF transmission is detected on the transmit frequency,
the Primary DVR starts transmitting i.e. repeating. If transmit activity is detected, the DVR
transmits momentarily then checks again if another DVR is still transmitting and either
backs off (if the other DVR is still transmitting) or keys up if no transmission is present.
Disabling the DVR Primary / Secondary Processing from the
Primary/Secondary Setup
Menu is intended for test purposes or if the DVR is installed in a fixed location. The
‘
Permanent Primary Status Enable’
field (in the
Primary/Secondary Setup
Menu) is
disabled by default and should be used only at remote, fixed DVR installations or during
testing. The
‘Rx RSSI Th’
field in the Repeater Channel Setup screen determines the
Primary / Secondary range. If a DVR is receiving Primary Heart Beat from another DVR
at a level lower than the programmed threshold, the DVR will ignore the Primary Heart
Beats and will negotiate becoming a Primary DVR as well. The
“Disable Primary /
Secondary Processing”
box is to be checked only during bench testing. Primary /
Secondary processing should always be enabled during normal DVR operation except
during bench testing and in some fixed isolated installations (tunnels or in-building
systems using common filtering / combiners).
If Legacy Mobexcom II voting compatibility mode is enabled in the DVR, its voting
algorithm is compatible with older style analog only Mobexcom II VRs. Enabling this
feature allows seamless replacement of old style VRs with the new DVR by supporting the
deployment of both types of units in the same fleet during the transition period.
