The Federal Communications Commission has issued warnings to 20 online retailers to stop selling illegal signal-jamming devices, including mobile phone, GPS and Wi-Fi jammers.
The sale and use of devices that jam the signals of authorized radio communications are illegal in the U.S., the FCC said, adding that it will "vigorously" prosecute violations from now on.
"Our actions should send a strong message to retailers of signal-jamming devices that we will not tolerate continued violations of federal law," Michele Ellison, chief of the FCC's enforcement bureau, said in a statement. "Jamming devices pose significant risks to public safety and can have unintended and sometimes dangerous consequences for consumers and first responders."
Jammers, which are sometimes used in theaters, churches and classrooms to avoid disruptions, can prevent people from contacting police and fire departments or family members in an emergency, according to the FCC.
If a retailer receives a second FCC warning, it could face fines from $16,000 to more than $110,000.
This version of this story was originally published in Computerworld's print edition. It was adapted from an article that appeared earlier on Computerworld.com.