Audio Buffering; Remote Dvrs Activation Via Dtmf; P25 Encryption In Analog Mode; Leading & Trailing Tones - Futurecom Mobexcom P25 Installation & Programming Manual

Audio Buffering

Audio buffering is supported by the DVRS in order to eliminate loss of messages / parts
of messages due to the inherent delays associated with acquiring system access.

Remote DVRS Activation via DTMF

The Local PSU may be programmed to remotely activate the DVR by switching it from
OFF or LOCAL to SYSTEM mode by sending a pre-programmed DTMF sequence (refer
to System Setup II for DVRS programming instructions related to this feature).
The remote activation only works if the Local PSU and the DVR are set to operate on the
same radio channel and there is no other Primary / Permanent Primary DVR in the area
operating on the same channel.
The DVR can not be switched OFF remotely via DTMF.

P25 Encryption in Analog Mode

If the MSU is receiving a P25 Encrypted call while the DVRS is operating on Analog
Channel, the DVRS can be programmed to do one of the following:

Forward encrypted audio to the Local PSUs

Forward Clear audio to the Local PSUs

Send Warning Tones to the Local PSUs and no audio
Leading & Trailing Tones
The DVR can be programmed to send over-the-air Leading or Trailing tones to the
LPSUs to indicate successful MSU key up / system access.
If Leading Tones are enabled, the LPSU operation involves the following:
1. User does a quick PTT of LPSU so that MSU can request channel grant
2. User releases the PTT for a moment and waits to hear the Leading tones.
3. If the Leading tones indicate successful system access (channel grant), the
LPSU user PTTs again and talks.
4. If the Leading tones indicate lack of channel grant, the LPSU user can try the call
again.
Trailing tones are sent at the end of LPSU transmission and therefore do not require
double PTT.
Both Leading and Trailing Tones are sent over-the-air (i.e. not generated in the PSU that
initiates the call) therefore all LPSUs that are within the DVR range and switch to the
DVR channel will hear the tones.

Mobile Detector

This feature applies only to Analog Simplex DVR Operation when
Simplex Mode" is Enabled
The Mobile detector feature is used when the MSU operates on a VHF or UHF
conventional half duplex channels without any base repeater.
When mobile detector is enabled (in the DVR and MSU) and the non Priority DVR starts
receiving transmission from an LPSU, the DVR directs the MSU to 'Listen Around' and
check if another MSU is handling the call. If no repeated transmission is detected from
another MSU, the DVR will start repeating the inbound PSU call.
The first few seconds of the LPSU transmission (inbound call) is always lost while
the DVR is checking for Priority Repeat.
Digital Vehicular Repeater Interfaced to XTL
April 2014
DVRS Installation & Programming Guide – PART II
(System Setup 1).
TM
5000 (O3 or O5) or XTL
8M083X01 Rev. 16
6881013Y39
"Fallback in Analog
TM
2500 (M5)
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