Just a few years or a decade ago, you or people around you must have owned a pager. It makes a "BP" sound and when it rings, you need to find a phone to call back. Hence, some people also call it "BP machine". However, with the emergence of mobile phones, pagers can now only be found in people's collections. Although pagers have disappeared long time ago, the legal cases caused by it has not yet ended. Recently, the Xuanwu Court in Nanjing has heard such a case about the pager fee in 1903.