North Korea continues to install cell phone jammers so that calls cannot be made across the border into China. Both countries use the same type of cell phone technology, and until the jammers were installed, it was possible for North Koreans near the border to call into China, and thus the rest of the world. People in China, could call across the border into North Korea. This is not good for the North Korean government, because it allows information to get into, or out, of the country too quickly. This is bad, because it enables unrest inside North Korea to spread more quickly, because information on unrest in one area gets into China, and there, the large number of Chinese Koreans use their cell phones to call back to people they know in North Korea.