The Forus DR7500 is a true telphone voice recorder equiped to give you long, clear recording time on 4GB of memory. What makes this recorder unique is the Auomactic Telephone Recording feature called TOR (Telephone line Operated Recording) this functions allow the recorder to stand-by consererving battery life.  When used on your land line telephone, the recorder will power down (stand-by) when you hang up and power on when you pick up thus extending the life of the batteries. All other telephone recorders contiune to use the batteries even when they are in VOR (Voice Activation recording). The sensitivity to sound/voice can also be adjusted. Features: Powers off when you hang up and powers on when you answer the phone to save power Adjustable sensitivity and sound 4GB of internal memory Up to 270 hours of record time Voice operated 20 hours of recording time on 2x AAA batteries Large LCD Display for easy set upForus