In 1874, L.H. McCollough invented the first mercantile alarm system. The first alarms systems utilized a single zone of protection that extended around the perimeter of the facility. The zone was nothing more than an electrical circuit that allowed current to constantly flow from one end to the other. When a door was opened, or a window was broken, the flow of electricity would be interrupted and the panel would cause an alarm. The panels would utilize a McCollough transmitter to send a type of code to the local police or monitoring facility. The McCollough transmitter was a wind-up device that was connected to a dedicated copper circuit. When the alarm was triggered, the McCollough transmitter would unwind and send a series of pulses along the dedicated copper wire.
The signal is best compared to a type of Morse Code or Telegraph Signal. After the alarm went off, the McCollough transmitter would need to be re-wound so that it was ready to send the next alarm.
The McCollough Receiver would tap out holes in stripes of paper. An alarm dispatcher would compare the holes with a list to pinpoint where the alarm had occurred. The earliest McCollough transmitters were utilized for fire alarm pull stations.
Needless to say, this forever changed the way that alarms were responded too. Fire Brigades could now respond much faster to the scene of a fire.
Alarm panels have come a long way since the days of the McCollough transmitter, but as a testament to the technology invented by McCollough, some of the most secure alarm transmission methods available today utilize a very similar technology.
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