fischertechnik Burglar Alarm

I protected my fischertechnik from being stolen. The question is only which side is protecting which. The grey side uses old "Silberlinge" to trigger a low frequency blinking circuit when the reed contact opens, which then in turn enables a faster audible tone generator. The black side uses the newer "Flip-Flop" integrated module (essentially acting as an inverter) to trigger a blinking module connected to a buzzer when the reed contact opens. Both reset once the reed contacts close again.