Abstract: An alarm system includes at least one wireless alarm transmitter, at least one wireless activate transmitter, and at least one wireless signal receiver. The signal receiver becomes sensitized to recognize an alarm code from the alarm transmitter after recognizing an activate code from the activate transmitter. The signal receiver can include an alarm generator that provides a first alarm after recognizing the alarm code. An alarm device can include a wireless hazard signal receiver that becomes sensitized to recognize a wireless transmitted hazard alarm code only after recognizing a wireless transmitted activate code. An alarm generator can provide a hazard alarm after recognizing the alarm code. The device can further include an alarm code and activate code decryption device. Instead of or in addition to the activate transmitter and sensitizing feature, the system can be equipped to display a location name in the alarm generator as a text alarm.