tams elektronik FCS Series Manual page 14

English FCS modules
FCS-4 "Emergency vehicle module"
While the vehicle is in motion the flashing lights double flash and the
siren is in operation with short breaks. When crossing a stop the back
lights are switched brighter for a short time as braking lights and the
siren is switched off (provided the reed contact which is in the vehicle is
connected to the module). As long as the vehicle is in operation the
flashing lights are switched on.
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