Installation guide

VAR4 / VAR12 / VAR20 - Product Description
3.3 Audio Outputs
The VAR Router provides 4, 12 or 20 (dependent on model) electronically balanced outputs. These provide
a nominal 0 dBu output, which when fully driven, corresponds to 100 V output from the ASL amplifier. Each
VAR Router output has separate A and B output connections for driving A&B amplifiers with interleaved
speaker circuits. The A and B outputs are isolated so that a short circuit on one output will not affect the
other.
The output is hard-limited to +2.5 dBu. The outgoing surveillance tone is not limited in this way. Thus if the
audio is overdriven, the surveillance tone is not clipped.
The outputs are normally fed from the DSP and all processing is performed in the digital domain. Each
output, is however equipped with an ‘override gain’ setting. This enables independent adjustment, for each
zone, of the level of the Fire Microphones when the VAR Router is in the hardware bypass mode. These
analogue gain settings are non-volatile and retained even after power failure and/or processor failure.
One additional output is provided from the routing matrix; this feeds the internal amplifier/loudspeaker for
Audio Monitoring functions.
The top two outputs of the VAR Router’s base unit and expand units can be configured to feed a 100 V line
driving an amplifier connected to an Induction Loop System, typically the ASL ILP01 Induction Loop Panel.
The number of induction loop outputs is configurable, and the induction loop outputs are allocated from top
down, as detailed in Table 2.
In addition to standard parameters an Induction Loop output has the following Induction Loop specific
parameters:
• Equalisation
Frequency bands suitable for the Induction Loop type can be adjusted to achieve as flat a frequency
response as is possible.
• Audio amplitude compression
The amount of compression and the threshold level at which the compression begins can be configured
in order to achieve the best intelligibility and general received sound quality.
The VAR Router provides test tones, which can be used during the commissioning of an Induction Loop
System. See Section “3.11 Test Tone Generation” for further details.
Issue: 03 complete, approved
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