ASL INTERCOM VAR4 - Induction Loop Output Surveillance Tone Generation Configuration

VAR4 / VAR12 / VAR20 - Operation Manual
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4. Move to, and scroll the possible surveillance tone generation modes until the required mode is
displayed in the left field:
[Mode=Pulsed] Level(dB)-12
A continuous surveillance tone is generated at the selected output.
sue: 03 complete, approved
13.3 Induction Loop Output Surveillance Tone Generation
Configuration
The audio path through the rack wiring to each amplifier, and through the amplifiers, can be monitored by
means of a low frequency surveillance tone with nominal frequency of 30Hz.
If selected this tone is generated by the VAR Router and superimposed on each audio output as required.
Surveillance tone generation is configurable either ‘off’, ‘on’ (continuous) or ‘pulsed’ per output. The outgoing
tone level per VAR Router output is also adjustable.
If surveillance is required then the advantage of the pulsed mode over the continuous mode is that less
power is used by the surveillance function in pulsed mode, while still providing the required surveillance. This
is specially important when operating from batteries.
If configured as pulsed, then the pulse interval is 20 seconds, and the pulse ‘on’ time is 1 second. The ‘on’
and ‘off’ envelope of the pulsed surveillance is shaped so that no audible artefacts can be heard at the
loudspeaker output.
In order to configure the surveillance tone generation proceed as follows.
1. Select ConfigurationÆSystemÆRouterÆOutputsÆConfiguration.
2. Scroll the output list and select the required induction loop output:
[O/P #1 - OUTPUT 01]
Default value: output 1
Outputs: 4 outputs for VAR4
12 outputs for VAR12
20 outputs for VAR20
Note: Not all of the VAR Router’s outputs can be configured to support Induction Loops; Table
details the possible induction loop output allocation.
The output name is shown on the right side of the display. The output name above is the
output 1 default name, however this may have been changed according to each site’s
configuration.
Standard output surveillance tone configuration is described in Section “12.4 Surveillance Tone
Generation Configuration”.
3. Move to, and select the Surv menu item.
Level Ind Loop [Surv] Override Name
• [Mode=Off]
Disables the generation of the surveillance tone at the selected output, e.g. when the VAR Router
output is connected to a non-ASL amplifier system.
• [Mode=On]