Two completely independent channels of detection monitor the two audio inputs. Each channel has an indicator for the presence of active audio, an adjustable silence level, and an adjustable delay before silence notification occurs.

When a silence condition still exists following the delay period, the silence alarms are activated. The red silence LED illuminates for the corresponding channel. An audible piezo alarm (defeatable) is also activated. (The audible alarm may be permanently disabled if required.) The two form-C gold relay contacts for the channel are also switched, allowing external devices (such as the RI-2) to be controlled or to route active audio for such applications as emergency backup audio switching.