A communication system (100) includes a control unit (101) electronically
coupled to a pushbutton switch (129). The control unit (101) includes a
wake-up circuit (110) having a signal generator (201) and a signal
detector (202). The signal generator (201) generates a digital pulse
signal (139) having a predetermined amplitude (303) and a predetermined
duration (304) for receipt by the pushbutton switch (129). The signal
detector (202) monitors the digital pulse signal (139) to determine
whether the pushbutton switch (129) is actuated or not actuated. The
communications system (100) maintains a low power consumption mode
responsive to determining when the pushbutton switch (129) is not
actuated, and enables a normal power consumption mode responsive to
determining when the pushbutton switch (129) is actuated.
