Magnetic field based power transmission line communication...
Magnetic key lock and alarm
Magnetic tamper detector
Magnetically triggered on-board elapsed time indicator
Magneto-optic bubble domain histograph
Malfunction detector system for item conveyor
Manipulation protection for a fire detector
Mannequin
Manual modular pull station
Manually programmable audible alarm system
Margin test switch for photoelectric intruder detection devices
Marker light arrangement for power lines
Master antenna line communication system
Maternity and life time tracking apparatus and method of use
Matrix address system using erase operation
Matrix discharge logic display system
Means for adjusting and for testing a detecting device
Means for distinguishing motion from noise in an intrusion alarm
Means for sensing change in the amount of fluent material in a r
Mechanically actuable control relay