... range:GSM,GSM,DCS,PHS and 3G signal ET101B Portable mobile phone detector1. TechnologyDetects wideband:a. can detects th RX frequency ... light(Blue)& RF detecting light(Red).*When it find the mobile phone signal, the red light will be on, much nearer ... .Working Area1, Every Examination room2, Conference room, theater, cinema, music hall etc3, Prison, jail4, Gas station, oil station, oil field etc5 ...