Background
As many radio systems used by fire and EMS agencies are migrating from conventional analog to digital P25 technologies, many IamResponding customers have asked about the ability to continue to receive audio incident notifications as their radios systems are updated.
This article explains how a Unication G5 pager can be used with IamResponding’s TwoToneDetect software to send audio alerts to IaR users on P25 trunked and conventional systems.
P25 Paging Methods
There are two primary methods of paging on P25 systems - Tone Paging and Talkgroup Paging. The configuration of the Unication pager and how it interacts with TwoToneDetect is different for each of these methods. This article is not a detailed programming and configuration guide for all aspects of the Unication pagers, but provides general guidance on how they can be configured for compatibility with TwoToneDetect.
Tone Paging over P25
When Tone Paging over P25 is used, the Unication pager should be set up in “open monitor” mode to simply act as a regular radio receiver for the frequency (conventional) or talkgroup (trunking) that the paging tones are sent over. TwoToneDetect is configured as usual to detect these paging tone frequencies that are sent over the air.
P25 Talkgroup Paging
When P25 Talkgroup Paging is used, there are no tones sent over the air for TwoToneDetect to detect. Instead, the “Custom Alert Tone” feature of the Unication pagers will be used. When the pager detects that the desired talkgroup(s) has activity, it will play an audio file with tones that can be detected by TTD.
Hardware
A Unication G5 pager with an amplified charger base is recommended. Use the “Audio” jack on the amplified charger base with a 3.5mm audio cable connected to the audio input / mic jack of the computer sound card that TwoToneDetect will be using.
Unication Settings for P25 Talkgroup Paging
Voice Buffering
To ensure that dispatch voice audio that is transmitted while the Custom Alert Tone is playing is not missed, the “Voice Buffering” setting on the pager must be enabled. This allows the pager to record the voice dispatch audio while the Custom Alert Tone(s) is playing. Once the alert tone has played, the recorded audio will then start playing.
Custom Alert Tone
IamResponding has a Custom Alert Tone audio file that is compatible with TwoToneDetect that can be loaded into the Unication pager. The audio file can be downloaded from this link:
https://download.iamresponding.com/twotonedetect/400_750.wav
In the Unication pager programming software, this audio file can now be used as a Custom Alert Tone as shown in the steps below.
Step 1
From the Tone List menu, click “Add”:
Step 2
Click “Browse” to select the IamResponding audio file that has been previously downloaded. You can also change the Tone Alias to reflect the tone frequencies, if desired. The audio files are named with an Atone_Btone.wav convention. For example, the 400_750.wav file in the example below has a 0.8 second 400 Hz tone followed by a 0.8 second 750 Hz tone.
Step 3
Once the audio file has been added to the Custom Alert Tone List, it can be selected as an Alert Tone for any Paging Group:
Step 4
The tones from the Custom Alert Tone can then be used in the TwoToneDetect Pager Groups Management page for detection:
Important Note: While different Custom Alert Tones can be configured for different talkgroups in the Unication Pager for detection by TwoToneDetect, there is an issue when multiple paging talkgroups are activated at the same time (multi-select, patching, etc.). In this case only the Custom Alert Tone for the first talkgroup that was detected is played by the pager. If TTD is configured to send notifications for multiple Pager Groups, only one notification (for whichever talkgroup that the pager detected first) will be sent.
If detection and separate notification of multiple talkgroups that may be sent at the same time over the air is necessary, please contact aknitt@rapidsos.com for potential alternative solutions.