US Patent 7295102 Panic alarm system controlled by remote transmitter

When an alarm switch of a transmitter is given a long press carried out for one or more seconds in a timer-reset condition, a first alarm reversal signal is transmitted simultaneously with the setting (starting) of the timer. If the alarm switch is pressed within the set time of the timer regardless of a press time period, a second alarm reversal signal is transmitted, and the timer is reset. On a receiver side, the activation and deactivation of the alarm is alternately performed upon receipt of each alarm reversal signal.