Federal law prohibits the use of radio scanners to intercept cellular phone calls, according to Privacy Rights Clearinghouse. It is illegal to sell or import radio scanners that have the capability to intercept cellular phone calls. Modifying radio scanners in order to intercept cellular phone calls is also illegal.
Cellular phones work by transmitting radio signals, which can be picked up by a radio scanner, advises Privacy Rights Clearinghouse. Although use of radio scanners to intercept cellular phone calls is illegal except by law enforcement officials, as of 2015, interception of cell phone conversations is extremely difficult since cell phones made after 2008 almost exclusively use digital signals, which most radio scanners are unable to decipher, according to Radio Scanner Guide. Law enforcement officials are able to intercept cell phone calls by using expensive scanners not available for sale to the public.