Abstract: A headset includes a first speaker coupled to a first compensation network and a second speaker coupled to a second compensation network. The headset also includes a differential sensing module configured to determine a differential signal between a first input signal associated with the first speaker and a second input signal associated with the second speaker. The differential signal is used to determine whether the headset is detected as worn by a user. A controller adjusts a power level supplied to the headset based on the differential signal.

Abstract: A service transport unit for providing utilities to a parked aircraft, by way of a utility bundle, comprising a box attached to a passenger loading bridge, at least one slider and corresponding utility bundle tracker slidably mounted within the box wherein the utility bundle is fixed to the outboard terminus of the slider. The slider is mounted in the box and affixed to the passenger loading bridge so that it is pulled from within the container by extension of the passenger loading bridge, and pushed back into the box when the bridge is retracted. The utility bundle is passively extended and retracted by movement of the slider. The slider and utility bundle tracker also serve to guide the utility bundle and prevent it from tangling or kinking during movement of the passenger loading bridge.

Abstract: A pulse-width modulated DC-DC power supply is illustrated with overvoltage protection which upon initial detection momentarily shuts down the pulse-width modulating portion of the control loop for a given cycle. If the overvoltage condition persists for more than a prescribed number of cycles or amount of time, the power supply is shut down permanently. The delay between momentary and permanent shut down being used to allow system operation to be maintained with minimal damage (voltage induced load stress) where large voltage transients may be temporarily introduced into the system.