The BART controversy and, to a lesser extent, the Standing Rock controversy, both show how complicated the shutdown signal can be in the United States-and how we truly fail to understand and resolve the blueprint for current and future law enforcement blackouts. What we do know is that it is still possible from a technical point of view almost ten years later. According to Joshua M. Pearce, a professor of materials science and engineering at the Michigan Technological Institute, there are two ways to cause ground power outages. (Turning off BART is an unusual situation because the authorities can access the device themselves.) The first is to ask (or require) the service provider to shut down a specific set of cell phone towers. It's as simple as a toggle switch
The second method (and a more difficult method) is to use jamming technology, which sometimes sends false signals, overwhelming the signal from the cell phone tower. Small short-range equipment can be purchased abroad (for example, equipment used by certain overseas universities can prevent fraud and lead to the suspension of a high school teacher in Florida in 2015). In theory, you can use a large number of small devices like this to call neighbors, but this is not convenient. Pearce believes that GSM jammer have a larger coverage area, but only organizations like the National Security Agency have them.