Variable system composition (6 or 12 household); ID setting by DIP Switch; Effective calling to all units by Paging function; Door lock release(optional); Easy identification of which sub-unit is in use by LED indication; Possible to use door phone by enabling DR-DW2N connection; Wiring: 4 Wires/ 500m(0.65ø); Power: DC 12V(RF-1A)en