Bosch Appliances 3922 988 43318 manual Environmental Conditions Maintenance, System, Public areas

Digital Congress Network Installation and Operating Manual Chapter 12 - Environmental Conditions & Maintenance en 12-1

Chapter 12. Environmental

Conditions and

Maintenance

12.1System

Where appropriate use cable ducts for extension and mains cables. In order to identify such cables consider using cable tallies.Trunk-lines where appropriate should be divided into manageable geographic locations - for example- use one trunk-line for committee members or dignitaries seated on a stage, and reserve, if appropriate one trunk-line for interpreter desks etc.. It is recommended that the chairman unit and interpreter desks are connected at the beginning of a trunk-line and not at the end. In public areas where connectors and cables could be trampled on, consider using protective metal covers according to the existing protection specification.

12.2 Public areas

12.2.1 Lighting

When placing contribution and channel selector units comprising an LC-display, ensure that the displays are positioned in such away as to avoid direct lighting or sunlight.The recommended viewing distance (due to the size of characters) is at arms length 1.5 m with a minimum light level of 50 lux, or even shorter for channel selector units without back-lighting so as to operate the unit while still having a good viewing angle.

12.2.2 Public displays (placement/viewing distance)

Place public displays in positions where they can be easily viewed by all participants concerned. Avoid placement in direct lighting or sunlight.The size and viewing distance for public displays shall be selected depending on the visibility criteria for each specific system. Aspects such as viewing distance, character size for hall displays, contrast an brightness under the usual lighting conditions shall be taken into account. Advise to be given by the equipment suppliers.

12.2.3 Public walkways

In public areas ensure that the cables attached to the system units, including extension cables, are run and laid out in a neat and tidy manner where they do not interfere and hinder public walk ways.

12.2.4 Headphones with interpreter systems

Where appropriate place headphones/headsets with the relevant contribution units and interpreter desks.

NOTE: Acoustic feedback, causing ‘Larsen’ effect (howling), is possible when connected headphones/headsets reproducing the floor channel with a high volume, come too close to an activated microphone.The minimum distance recommended between microphone and headphones/headsets to avoid the ‘Larsen’ effect, depends on the type of headphones/ headset, the volume setting and if worn or laid down on a desk or table. User should be instructed to keep sufficient distance or to set the volume level not louder than necessary.

12.2.5 Recommended speaking distance

The recommended speaking distance from microphones is 30 cm (1 ft.).

12.3 Technical rooms

It is recommended that in technical rooms where DCN’s central control equipment is housed the following conditions should be met:

•When units are mounted in a 19” rack ,sufficient rack space is required between heat generating units to allow proper ventilation. Proper precautionary measures should also be taken inside the rack (e.g. forced ventilation inside racks) to keep the ambient temperature well below the maximum allowed temperature so as to extend the life-time of the equipment.

Refer to Chapter 13.. ‘Technical data’ for the allowed temperatures.

•Ensure that the area is a dust-free environment.

•Ensure adequate air-conditioning.

•Ensure adequate ventilation.

•Ensure adequate lighting. But ensure that the lighting does not impede the central operators.

•Do not place objects on top of the units, which could fall into vents or which could cover them and prevents proper cooling of the units electronics.This could infiltrate into the unit which could cause trouble such as fire and electric shock.

•Do not expose units to rain or excessive moisture to avoid the risk of shock or permanent dam- age to the system units.

•Do not attempt to remove the top cover of the Central Control Unit, Audio Media Interface Unit and Extension Power Supply Unit as you will be exposed to a shock hazard.The covers should only be removed by qualified service personnel.The units are designed for indoor use only. Please refrain from subjecting the units to vibration, and never place the units near or over a radiator, heat grill or in direct sunlight.

•In PC based systems, be warned that placing a magnet or loudspeaker system in the vicinity of the PC will corrupt data files stored on the hard or disk or floppy disks.

WARNING: Damage to the power cable may cause fire or a potential shock hazard.

Bosch Security Systems 04-2003 3922 988 43318 en System