Invisible electronic fences can prevent catastrophe
Invisible electronic fences or fenceless borders is an electronic system designed to guide pets or other pets along a set of predetermined boundaries without the use of physical barriers. A slight electronic shock is delivered via the electronic collar if the prior audible warning of the animal is not sufficient. The system was invented and patented by Richard Peck back in 1973 and was held by Invisible Fence Co, now known as Invisible Fence Inc, until 1990 . Due to the small amount of shocks, we do not use the term electric fence, fence.
Invisible electronic fence technology , fences
The pet wears a light collar that emits a warning sound as the pet crosses the border. If the warning is ignored and the pet crosses the fence, the pet gets a mild electric shock from the collar. The stimulus received by a pet can be used more often and with greater power as the animal approaches the border. The pet soon learns not to cross the border and avoid the invisible location of the fence, making it an effective virtual barrier. Animals (including humans) that do not wear a collar are not affected by the restrictions.
Although these invisible fences are referred to as "wireless fences," these fences are less accurately designated as electronic pet restraint systems. In cost analysis, they turned out to be much cheaper and more aesthetically pleasing than physical fences.  However, electronic fencing may not be effective if the animal crosses the line of excitement.  House fences are also sometimes used for livestock in circumstances where conventional farm fencing is not appropriate or legal, for example on British common land .
Variants of electronic invisible fences, fences
In some invisible pet fencing systems, there is a wire (which can be buried) that emits a radio signal to activate the receiving collar. Other house fences are wireless. Instead of using an underground wire, they emit a radio signal from the central unit and activate when the house cart exceeds a certain radius from the unit.
The second is a collar that uses GPS signals to determine the proximity of a predefined "virtual fence" without the need for physical installation. This system allows for additional flexibility, such as simpler integration of "islands" within the containment area and easier border changes, although the location of the border is not accurate due to GPS tolerances.
In addition, some collars have multiple settings, allowing owners to have a collar of just a tone or one of several levels of static shock, with higher levels being used for larger and stronger dogs. 
An underground fence is an electronic system that prevents an animal from leaving the yard. For the dug wire around the area being used, it is filled with coded signals. As the pet approaches the buried fence line, the ring makes a warning sound and then sends a harmless electrical pulse to the pet.
The first commercial underground pet fence system in a predetermined area was patented by Richard Peck, owner of the Invisible Fence Company in 1974. The Peck underground fence was also the first limitless livestock containment system. In 1987, Peck successfully cared for domestic goats in a restricted area with RF clamps designed for dogs.  Invisible Fence, Inc. is currently owned by Radio Systems Corporation.