Microphone Unit: Nvt-161 - JRC JCY-1800 Installation Manual

3.5. Microphone Unit: NVT-161

3.5.1. Selecting the Location
The Microphone Unit collects conversations in the bridge, other voices through the public addressor and
the intercom, and alarms buzzers of the group panel installed in the bridge. The locations of the
microphones should be carefully selected so that they can record vital voice communications.
3.5.1.1. Recommended Location
Although the number of microphones needed depends on the bridge layout, in most cases three
microphones will do. The recommended locations for mounting microphones are:
1) The overhead panel or the ceiling above the main conning station.
2) The overhead panel or the ceiling above the main route planning station i.e., the chart table.
3) The overhead panel or the ceiling in the vicinity of the radio transceiver.
3.5.1.2. Notes on selection
Consider the followings when selecting a location for mounting a Microphone Unit.
Microphones can collect conversations within a radius of 2.5m. Any obstacles or sources of noise
(60dB or more) should be kept out of this range.
1) The microphone unit should be away from any ventilator or draft.
2) The microphone unit should be away from electric apparatuses such as the RADAR, radio
communication equipment, and so on that may emit an excessive electromagnetic field.
3) The microphone unit should not be exposed to excessive vibration.
4) The microphone unit should be in a compass safety distance of 0.5m.
3.5.2. Fastening a Microphone Unit
A Microphone Unit can be mounted in or on the ceiling, a bulkhead, or a console panel. When mounting
it in a console panel, cut out the panel surface in the shape as shown in the figure in the next page.
Or when mounting it on the surface, remove the flange from the Microphone Unit.
Any Microphone Unit has 2 wiring holes.
It has a label for the unit number on it. Confirm the location of the label and make sure that the unit
number on the label is equal to what is written in the instruction drawing.
JCY-1800/1850 VDR/S-VDR Installation Guide
47
3. Mechanical Installation
DOC No. 7ZPJD0387C