- Internal Sonalert audible alert--continuous or pulsing
- Positive delay adjustment via rotary switch
- Delay adjust accessible on rear panel
- Logic-level alert voltage built in
- Audio detect mode
Trigger alert or terminate transmission on loss of audio
The AFS-3 Audio Failsafe monitors one or two audio signals and maintains a relay contact closure as long as audio is present on at least one of the two audio inputs. When no audio is present on both inputs for a preset length of time, the relay contacts open and remain open until audio is present on either input again. To eliminate false triggering, audio on both inputs must be silent for a preset length of time. The length of this delay is adjustable from 30 seconds to 5 minutes in thirty second increments.
The AFS-3 is typically used as an alternate control for a broadcast transmitter. When properly installed, the AFS-3 can turn off a transmitter by silencing the audio feed to the transmitter. This procedure would normally be used only when the normal remote control system or telephone line has failed. Alternately, the AFS-3 can supply a logic-level voltage shift to an outboard piece of equipment such as a transmitter remote control that can respond to the alarm condition and contact station personnel.
The AFS-3 is housed in a small metal chassis that is attached to a single rack space size panel. It is designed for mounting in a standard 19” wide equipment rack. All connections are made through pluggable screw terminal connectors on the rear panel. Front panel indicators include power, system enabled, audio present and alert status. Controls include a front panel defeat switch, rear panel delay adjustment and internal jumpers to select options such as an audible alert (Sonalert) and logic voltage on the ouput relay. Both normally open and normally closed relay contacts are available.
The AFS-3 also works in reverse as an audio detector instead of a silence sensor. Normally a delay period of silence is necessary to trigger an alert. In reverse, a preset period of audio can be used to trigger an alert. Honestly, we don't know of a specific application for this mode yet, but it's there if you need it.
