ISS has released its Mobile Blocker jamming device that can block wireless phone and pager signals within a 40-meter (135-foot) circle. Using an encoded signal from a base transmitter that is emitted at the same frequency of pager and cellular communications , the ISS blocker prevents calls from being received or initiated and delivers a text message such as "No Service" or "Out of Range" to the devices, the company explained.

Seeking Peace and Quiet

The device is compatible with many cellular networking systems, the company said, and includes antennas for multidirectional blockage and an optional remote switch for immediate on/off control of the transmitter in case of emergency. It works on all digital and analog phones.

Mobile Blocker was developed at the request of an international customer, which the company declined to name, that wanted to block mobile phone and pager use during religious services, ISS said. "This is a cost-effective solution to maintain a quiet environment for places of worship, theaters, restaurants, boardrooms and museums," said Bill Sowell, vice president of business development at ISS.

Canada Considers Jamming

The legalization of cell phone jamming devices is currently under evaluation in Canada, Hong Kong and other locations worldwide, Sowell said, adding that Mobile Blocker is approved for sale and use in parts of Europe, Scandinavia, the Middle East and Asia. The sale and operation of the device is restricted only to countries that permit the operation of such devices by approved agencies or private businesses, the company said.

The Canadian government is seeking public input on the licensing of wireless phone jammers with an eye toward eliminating the use of cell phones and other mobile devices in such public places as theaters, restaurants or libraries.

That move prompted a response from the Canadian Wireless Telecommunications Association, which contended that phone silencers would jeopardize public safety and infringe on the rights of Canadian citizens. Presently, only public safety and law enforcement agencies have licenses for cell phone silencers in Candada.

The ISS blocker is not commercially available in the United States, as the U.S. Federal Communications Commission (FCC) prohibits mobile phone jamming. However, the company said tribal lands owned and occupied by Native Americans are considered sovereign terrritory, and the use of blocking devices on those territories is permitted with proper authorization.

Based in Saint Paul, Minnesota, Image Sensing Systems produces video imaging technology for traffic management systems abd wireless transmission products.