Two wires two-families audio kit with Linea 2000 (wall-mounting) entrance panel and Sprint L2 handsets. Keys available on handsets : door lock release and 1 configurable key for auxiliary functions (e.g. stair lights activation, entrance panels activation / cycling, call to the switchboard). Clamps for the external call to the floor pushbutton connection. Ringtone volume adjustable on 3 levels.