Environmental Conditions And Maintenance; System; Public Areas; Technical Rooms - Bosch DCN Next Generation Installation And User Instructions Manual

DCN NG | Installation and User Instructions | Section 5 | System Installation
24 Environmental conditions
and maintenance
24. 1

System

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. In public areas where connectors and cables
could be trampled on, consider using protective metal
covers according to the applicable protection
specification.

24.2 Public areas

24.2.1 Lighting
When placing channel selector units, ensure that the
displays are positioned in such a way as to avoid direct
lighting or sunlight. The recommended viewing distance
(due to the size of the characters) is at max. 1.5 m with a
minimum light level of 50 lux so as to operate the unit
while still having a good viewing angle.
24.2.2 Displays
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 and brightness under the usual
lighting conditions shall be taken into account. Advise is
to be given by the equipment suppliers.
24.2.3 Walkways
In public areas, ensure that the cables attached to the
system units, including the extension cables, are run and
laid out in a neat and tidy manner where they do not
interfere and hinder public walkways.
Bosch Security Systems | 2004-03 | 9922 141 70521en
24.2.4 Headphones/headsets
Where appropriate, place headphones/headsets with the
interpreter desks. 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/headsets, the volume setting and if worn or
laid down on a desk or table. The users should be
instructed to keep sufficient distance or to set the
volume not louder than necessary.
24.2.5 Speaking distance
The recommended speaking distance from microphones
is 20 - 30 cm.

24.3 Technical rooms

It is recommended that in technical rooms where
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 to extend the life-time of the
equipment.
• Ensure that the area is a dust-free environment.
• Ensure adequate air-conditioning.
• Ensure adequate lighting, but also 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
prevent proper cooling of the electronics of the units.
This could infiltrate into the unit which could cause
trouble such as fire or electronic shock.
en | 129