10 some suitable positive pulse suppression circuitry 72 a 72 b will attenuate the output from the differentiator 68 a 68 b for approximately 1 ms the comparator monostable vibrator stages 70 a 70 b determine whether the output from the differentiators 68 a 68 b with or without attenuation exceeds a defined minimum threshold the defined minimum threshold corresponds to the rate of change of pressure associated with a rapid decompression event that requires the unlocking or unlatching of the door 18 to allow rapid equalization of pressure throughout the aircraft 10 the comparator monostable vibrator stage 70 a 70 b provides signals to an output stage 74 the output stage 74 is coupled to control the solenoid 36 of the latch mechanism 21 a suitable output stage 74 may take the form of a mosfet transistor with a driver that can be driven from either one of two pressure sensing channels or from an external input in one embodiment the external input signals place the solenoid 36 in an on state when a ground 0v is present at an appropriate input pin in this embodiment the solenoid 36 is in an off state when a high impedance is present the output stage 74 may also include current limiting to protect the mosfet from excessive currents the microprocessor 64 is optional in the controller 22 of the control access system 20 in the typical embodiment the rate of change sensing circuitry 66 68 70 74 as well as the positive pulse suppression circuitry 72 will take the form of an analog circuit to realize the desired high speed operation of the rate of change sensing functionality given the.