Cell-Site Simulators/IMSI Catchers
Cell-site simulators, also known as Stingrays or IMSI catchers, are devices that masquerade as legitimate cell-phone towers, tricking phones within a certain radius into connecting to the device rather than a tower.
Cell-site simulators operate by conducting a general search of all cell phones within the device’s radius, in violation of basic constitutional protections. Law enforcement use cell-site simulators to pinpoint the location of phones with greater accuracy than phone companies. Cell-site simulators can also log IMSI numbers (unique identifying numbers) of all of the mobile devices within a given area. Some cell-site simulators may have advanced features allowing law enforcement to intercept communications or even alter the content of communications.
It’s not just law enforcement. Some shopping centres (“malls” if you’re in that part of the world…) have similar things. Prisons may also have them, to “block” mobile phone communications.