North Korea used jamming equipment to block South Korean military communication devices last week, a report said Sunday, amid high tension over the joint drills between Seoul and Washington.
Yonhap news agency said strong jamming signals sent across the border on Friday had caused minor disruptions to phones and navigational devices using GPS (Global Positioning System) at military units near the capital Seoul.
The signals are believed to have been sent from the North's military facilities in Haeju and Kaesong close to the heavily-fortified border, it said, citing Seoul intelligence and military officials.
"The signals were sent intermittently every five to 10 minutes... we suspect the North was testing new GPS jamming devices imported from overseas," said an intelligence official quoted by Yonhap.
"We are preparing systems to control and overcome such jamming signals," it quoted another official as saying.
more
http://www.physorg.com/news/2011-03-korea-gps-devices.html