A radio control system in a wireless communication device includes a sensor operable to detect a change in a use mode of the wireless communication device during a communication session according to a pre-determined list of conditions, the use mode being one of a plurality of use modes that the communication device can operate in. One of the least two cants may be sawed in half lengthwise with the cut parallel to the flats and then the half cants are glued to the other cant flats-to-flats. This door monitoring system may have a separate power supply for applying a back-up voltage to a door circuit in the event that the VMC fails to supply the voltage. The seat assembly includes a flow portion and a securement portion. At least a portion of the power transmission mechanism is positioned below the carriage when moved to an end part in the second direction. The thinness of the projection screen reduces visual dead zones.