A hazard alarm and alarm system enables a plurality of hazard alarms of multiple types (e.g. smoke alarms, heat alarms, motion detectors, carbon monoxide alarms, gas alarms, and the like), to communicate with one another without generating conflicting alarm warning indicators. Electronic circuitry is also provided, that may be added to at least one of the hazard alarms, for transmitting and receiving digital information with other hazard alarms connected thereto.