Once upon a time we hired security guards to controll access to our buildings. They’d check your credentials before allowing you to pass.
Today we use access control systems that are less expensive and more accurate. But most people don’t have a clue on how these systems work and falsely believe some kind of hocus pocus is occurring in the background.
Actually, they are very simple.
Everyone knows how to turn on a light bulb.
But before we ever throw the switch we must understand power is already being fed to that switch. It is just sitting there patiently for us to come by and send power down the line to the light bulb.
Once the switch is thrown, power is fed to the bulb and it will obviously light up. Not exactly rocket science.
Access control systems work the same way. Power is fed to a switch and it sits there patiently for it’s time to jump into action.
Of course switches used in access control don’t look like light bulb switches, but they do operate on the same principle. They toggle on or off. There is no in between.
Some switches are operated by human beings. A ”Push To Exit” button or an entry keypad require us to interface with them before action is taken. Other switches don’t need us to be there at all for them to jump into action. A timer, for example, might kick on at 10:00 PM all by itself. We have programmed the unit to do its thing at a preset time.
There are all kinds of switches used in access control, and some even are tied together in a single system. As an example, we might walk up to a secure door and enter a code on a keypad. That keypad sends a signal down the line to release the mag lock on the door. So far so good. But that mag lock has its own built in timer that is set to remain unlocked for only six seconds. When the six seconds are up it reverts back into locked mode again.
So in this example two switches were used to provide the desired operation.
But at the end of the day these are nothing but on/off switches. They are dumb and do not think. There is no hocus pocus occurring in the background that is mysterious or hard to understand. These little devices just do their on/off thing, time and time again, every time being exactly the same.
