C-Tec VA405X FMIC Emergency Microphone (up to 4 Per System)

The VA405 has been designed to offer a simple life safety microphone for AVAC voice alarm systems for global emergency voice announcements. It comprises a close-talking noise-cancelling fist microphone, speak-bar, two status indicators (OK and Fault), all housed in a red steel wall mount enclosure with a clear window and lockable door. To make an emergency announcement, the thumb switch on the fist microphone is pressed. The speak-bar will be lit solid green and speaking may commence.

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. The control lines are monitored using voltage divider techniques.