The supply pin is used for charging the battery as well as for supplying external devices. The distinction between charger and external device like light gate is done by the detection pin. The device is charged with a 15V DC charger, the voltage level for external devices is 12V.
The two pins Trigger 1 and Trigger 2 are independent of each other and not connected internally. The maximum voltage for these pins is 15V. To prevent false triggering these pins are provided with a hysteresis:
