By default, ocBridge Plus response period is set to ping detectors every 36 seconds and to signal an alert after 40 undelivered passes. Under these settings, it will take about 24 minutes for the system to recognize a communication failure.
You can adjust these settings by opening the Ajax configuration settings and connecting to ocBridge Plus. Find the Service Events Control tab, then Lost Connection, and change Passes Number. You can change response period in the Radio Zone tab.