Avail understands that in systems where myAvail controls operator access to the voice radio, operators must have voice communications with dispatch if the system is down. For cases when a closed mic system is down, the agency automatically reverts to open mic until the system is restored, to ensure essential communications are available.
The vehicle operator will see that the MDT Status Bar indicates when the MDT is not communicating with the system:
The vehicle operator will also see Voice Fallback display on the MDT screen, so they are aware that the closed mic system is temporarily down and the open radio is active until service is restored:
Closed Mic refers to cases where myAvail manages operator access to voice communications to dispatch through the RTT (Request to Talk) and the PRTT (Priority Request to Talk) buttons on the MDT. Operators are required to request permission to talk via the MDT. When dispatch creates the call, after the request to talk has been placed by the operator, the operator will pick up their handset to join the call with dispatch. Operators cannot talk directly to each other, a supervisor, or the dispatcher without the dispatcher creating the call. Also, operators only hear calls that the dispatcher has specifically allowed for that vehicle. Closed Mic operation is optional for private radio systems, and it is required to configure VoIP (voice over internet protocol).
The Communications Control Module (CCM) device has a ‘watchdog’ mechanism that will detect a myAvail failure. The CCM periodically communicates with the IVU, which in turn pings the MDT. The IVU responds to the CCM, and that determines the MDT status. If the CCM does not receive an IVU response within a timeout period or receive a response that indicates an MDT problem, the CCM resets power to the MDT and IVU. This action causes them both to reboot, re-establish connectivity, and restart their processing. This failsafe mechanism helps the system recover from unexpected connection and processing problems. If this process does not restore normal operations, communications go into Voice Fallback mode automatically.
In a private radio system, the radio falls back to Open Mic. In an Open Mic configuration, everyone on the same frequency hears everyone else talking. No prior action is needed to speak on the radio.
VoIP communications has its own fallback. The VoIP processing is isolated from the MDT-IVU units. When the central system has a communication problem, the CCM puts the VoIP processing into a voice-fallback mode that allows the driver to use the handset to make and receive direct voice calls with dispatch without obtaining permission.
When vehicles go into voice fallback, IT personnel must determine whether the problem exists in the communications connection to the tower, communications software, radio equipment, or cellular provider. If your property’s support agreement includes the radio system, contact Avail Support and they will have a radio shop check the tower.
If the vehicles are not able to communicate over the radio data channel system, but the vehicles continue in Closed Mic operation, then disable the WiNG service. This action forces vehicles to voice fallback until the problem is resolved.