Automatically release the line if the phone is not put down well or if it is off hook and the line is busy allowing a incoming call Ringer with LED Visual Light Green LED Lights and sound when phone is off hook (Handset is not on hook) Adjustable timer 15Minutes, 30Minutes ,60Minutes or unlimited Minutes Loud telephone ringer 95dba Adjustable ringer switch Adjustable tone switch Very bright LED Works on PSTN / VOIP / Cable lines Uses Regular RJ11 plugs A/C Adaptor Supplied Desk and wall mountable Connects easily to telephone FCC Approved