Company had been advertising 285 models of jamming devices to US customers.
Chinese technology company C.T.S. Technology is facing a record $34.9m fine from the US Federal Communications Commission (FCC) for illegally marketing cellphone and radio jamming equipment in the country.
The Shenzhen-based electronic manufacturer and online retailer had been marketing 285 models of jamming devices to US customers for over two years, an investigation found.
Acting Chief of the Enforcement Bureau Travis LeBlanc said that signal jammers present a direct danger to public safety, potentially blocking the communications of first responders such as ambulance drivers..
"Operating a jammer is also illegal, and consumers who do so face significant civil and criminal penalties," LeBlanc warned.
Signal jamming devices radio frequency transmitters which can intentionally block communication system such as cellphone calls, GPS systems, Wi-Fi networks, and first responder communications.