How Invisible Fence Works
Understanding the Invisible Fence system
The Invisible Fence system, like all hidden fencing, works through basic conditioning. When the dog approaches the fence, the dog collar starts beeping. If the dog ignores the beeping and stays near the fence for more than three or four seconds, an electric shock is delivered to the dog's neck through two blunt electrodes. The dog leaves the fence area to avoid further shocks.
It sounds harsher than it really is. The shock is more surprising than it is painful. After training, the dog learns to heed the warning beep and move away from the fence before the shock occurs. Simple, but very effective.
The nice thing about the Invisible Fence system is that both the collar and the control unit are computerized. The control unit sends encoded pulses along the hidden fence that only the collar knows how to decode. Other wires do not trigger the collar, so no random shocking ever occurs. The collar is also smart enough to warn the dog before delivering a shock. (Avoid pet containment systems that don't use computerized collars, otherwise your dog may get shocked for no particular reason due to stray electrical fields. And make sure the dog gets warned and has a chance to correct its behavior.)
You can also purchase separate wireless control units for indoor use. These units emit the same encoded pulses that the regular unit transmits through the wire, only these pulses are broadcast directly in the air in a circular pattern around the unit. They can be used to keep dogs away from specific rooms or areas inside the house if normal pet containment measures (like a "doggy gate") don't work. We use one of these units to keep Barney out of the living room, since he'll happily hop over the doggy gate otherwise.