Desk Microphone Console Black

Description

Desk Microphone Console

The VA406 has been designed to offer a microphone for AVAC voice alarm systems for public address paging. The Console comprises a sturdy ABS case c/w a high quality flexible gooseneck microphone a speak-bar (push-to-talk button) an LED output level meter and two status indicators (OK and Fault). To page the microphone’s speak-bar is pressed. The speak-bar will be lit solid green and speaking may commence. This microphone may be used as an emergency microphone (instead of the VA405) provided it is located in a secure position where it cannot be tampered with.

TECHNICAL DESCRIPTION
Speech is picked up by the microphone and the signals are passed to a voltage controlled amplifier under control of a signal derived from rectifying the stage output signals providing a 3:1 compression ratio. The output of this stage is fed to an LED output level display and a three-band equalizer (100 Hz 1 kHz and 10 kHz). The audio line is monitored for faults by means of a 15 V phantom voltage that is injected from the AVAC (only applicable when connected to the emergency microphone input).

FAULT MONITORING (only applicable if connected to the emergency microphone input)
When the Mic. Monitor jumper link is in the ‘Enable’ position the microphone capsule is monitored for impedance and current absorption. Any deviation outside this pre-set window is detected as a fault which lights the Fault LED. The audio lines are monitored by the phantom voltage detect circuit which notifies any loss of the 15 V phantom (due to an open circuit or short circuit line) to the monitor circuit. The monitor circuit causes an open circuit condition to be set on the PTT signalling a fault to external control equipment.

CABLES
The VA406 is provided with a 2 metre flexible lead terminated in an RJ45 plug. This plug connects to a CatCON wall plate which fits on a dual single gang wall box in order to provide enough space for termination. A single gang blank plate should be fitted over the unused part of the back box. If the VA406 is used as an emergency microphone then two 1.5 mm2 four-core fire-rated cables should be used to connect the AVAC. Maximum distance is 500 metres. If the VA406 is used as a paging microphone then a single Cat5 cable should be used. Maximum distance 500 metres.