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A simple surveillance function may be realized by
means of the ‘failure detect’ connection in case the RS-
485 network interface is not used. Three relay contacts,
‘normally open’ (NO), ‘normally closed’ (NC) and
‘common’ (COM) are available on this connector.
If the autogain function of the Intellivox is used, a
separate ambient SPL/temperature sensor has to be
installed and connected. This automatic volume
adaptation feature will only function properly if the
signal, which is detected by the microphone inside the
sensor, is representative for the diffuse ambient noise
level. For this reason the sensor should be kept away
from direct sound sources such as talking people,
outlets of the air conditioning system or other
loudspeakers. The implemented software protocol
freezes the volume setting when an audio signal is
present in order to prevent ‘hunting’ of the column’s
gain setting caused by its own acoustical output. All
relevant autogain parameters can be adjusted by means
of the RS-485 interface. In practice, the most favorable
sensor locations are walls or ceilings (height > 3 m)
within a range of 25 m of the corresponding Intellivox
(see also chapter 3.4).
If the ambient temperature is expected to exceed 40°C
an external fan should be connected to ensure proper
operation of the Intellivox under all circumstances. For
this purpose an external 24 V relay should be
connected to the terminal block marked ‘Fan Relay’.
Because of the limited drive current an external relay
must always be used to switch the fan, do not connect
a fan directly to this terminal! The external relay (if
connected) will be engaged if the heatsink temperature
exceeds the threshold. The fan should be mounted on
a location ensuring sufficient airflow along the heatsink.
In case the Intellivox is installed outside or in another
environment with a high expected humidity, the
electronics should be treated with an insulation
substance to prevent defects due to condensing
moisture. If specially ordered, this can be done during
the manufacturing process.
To prevent damage to the loudspeakers due to frozen
moisture inside the voice-coil gap, each Intellivox is
equipped with a ‘frost protection’. If the ambient
temperature drops below a certain threshold the
internally generated pilot tone for the frost protection
will be activaded. The aforementioned ambient
SPL/temperature sensor should be installed for this
function to operate properly. The switching threshold
and hysteresis can be adjusted through the RS-485
interface.
Intellivox DDC | Installation Manual | Installation Guide
Bosch Security Systems | July 2003
EN
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