Advantage : Digital coding system avoids false ringing and miscommunication between you and your guests , 1/20000 different encoded frequency couples provides strong anti-interference and enable you to receive the ringing accurately . 100 meters remote-control distance can suit for various building such as house ,apartment , office, stores ,workshops , garages , and reception areas ,etc .It also can be used as a pager . Power : 220V , AC , Flat plug in or Two round pin plug in . Packing : Blister , Chinese and English version ,