Bosch PRAESENSA - Line Input; Technical Data

PRAESENSA Installation wiring | en 87
Bosch Security Systems B.V.
Underwriters Laboratories Listing Document (ULLD)
2021.12.21 | V0.15b | F.01U.402.882
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.
i
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
isolator cable.
3.8.7 Technical data
Electrical
Microphone (PRA-CSLD)
Nominal acoustic input level (configurable) 80—100dBSPL
Maximum acoustic input level 120dBSPL
Signal to Noise Ratio (SNR) >70dBA
Directivity Unidirectional