Line Input; Technical Data - Bosch PRAESENSA Manual

PRAESENSA
3.8.6

Line input

On the left side of the call station is a 3.5 mm stereo socket. This is an input for a background
music source, such as a dedicated audio player, smartphone or PC. The connected audio
player, smartphone or PC must always be located in the same room.
The stereo signal is converted to mono for further distribution in the system. This input is not
supervised, unplugging the cable to the audio player will not be reported as a fault.
Notice!
When music is played from a PC that is connected to a grounded mains supply, there is a risk
of hum being inserted into the music input of the call station. This is caused by unequal
ground potentials of the different mains supplies. Use a cable with integrated transformers
for ground loop isolation to prevent such hum. See picture below of an example ground loop
i
isolator cable.
3.8.7

Technical data

Electrical
Microphone (PRA-CSLD)
Nominal acoustic input level (configurable)
Maximum acoustic input level
Signal to Noise Ratio (SNR)
Directivity
Bosch Security Systems B.V.
Underwriters Laboratories Listing Document (ULLD)
Installation wiring | en
80 — 100 dBSPL
120 dBSPL
> 70 dBA
Unidirectional
2021.12.21 | V0.15b | F.01U.402.882
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