A CPA did not want to be disturbed during tax season, so he used a small, inexpensive cell jammer inside his office. The jammer ended up disrupting communications of a nearby Fire Department. In another instance, a high school teacher used a jammer in his classroom. Unknown to the teacher, the jammer was blocking all teachers, students, and staff throughout the school from making any calls, including emergency calls.
It is against the law to use a cell or GPS jammer or any other type of device that blocks, jams or interferes with authorized communications, as well as to import, advertise, sell, or ship such a device, warns the Federal Communications Commission (FCC). The FCC Enforcement Bureau has a zero tolerance policy in this area and will take aggressive action against violators, warns the agency.
Violations of the jamming prohibition can lead to substantial monetary penalties (up to $112,500 for any single act), seizure of the illegal jammer, and criminal sanctions including imprisonment.
Unless you are an authorized federal government user, you may not operate a jammer in the U.S., even on private property. If you purchase a jammer online and ship it to the U.S., you have violated federal law. You may not sell or advertise jammers to individuals or businesses on online auction or marketplace sites, in retail stores, or even at your local flea market. Selling even a single jammer is illegal.
What are “jammers”?
Generally, “jammers”—which include devices commonly called signal blockers, GPS jammers, cell phone jammers, text blockers, etc.—are illegal radio frequency transmitters that are designed to block, jam, or otherwise interfere with authorized radio communications.
How do jammers work?
A jammer can block all radio communications on any device that operates on radio frequencies within its range (i.e., within a certain radius of the jammer) by emitting radio frequency waves that prevent the targeted device from establishing or maintaining a connection.
Jamming technology generally does not discriminate between desirable and undesirable communications. For example, jammers can: prevent your cell phone from making or receiving calls, text messages, and emails; prevent your Wi-Fi enabled device from connecting to the Internet; prevent your GPS unit from receiving correct positioning signals; and prevent a first responder from locating you in an emergency.
You can read more on jammers here.