Installation guide

VAR4 / VAR12 / VAR20 - Product Description
3 Audio Router Functions
3.1 Architecture
The diagram in Figure 5 shows the audio architecture of the VAR20. The other variants have an identical
architecture but reduced numbers of Mic/Line Inputs and DVAs.
The majority of audio processing functions are performed by DSP software. However, inputs 1 and 2 support
failsafe Fire Microphone routing whereby the DSP elements are bypassed in the event of processor failure or
software mis-operation. The Voice Alarm system is available for emergency announcements within 1.5
seconds of power-up. To achieve this, the VAR Router goes into to failsafe override mode:
• immediately after power-up; and
• immediately after a reset causing a reboot sequence.
So that the Fire Microphones are available for All-Call announcements.
Adjustable parameters are shown in the grey boxes in the figure. These are controllable by the user interface
menu system described in the VAR Router Operation Manual.
3.1.1 Audio Routing
The VAR Router is able to concurrently route any of the potential input sources to any of the outputs.
Inputs are assigned priorities so that higher priority inputs override lower priority ones; see Section
“3.4 Audio Input Priority and Override”.
Five types of routing of the audio inputs are provided·
• Permanent Route
See Section “3.8 Permanent Routes”.
• Latent Route(s) activated by contact closure(s)
See Section “3.7.3.1 Routing”.
• Under the control of Microphone Station
See Section “3.2.1 Mic/Line Inputs”.
• Under Control of Fire Alarm System (DVA Routing)
• Remotely by a host computer via a serial interface
Issue: 03 complete, approved
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