Ameriphone VCO Telephone Powerful adjustable amplifier allows incoming volume up to 26+db Adjustable Tone Control-allows you to adjust the tone of incoming sound to enhance the clarity and to help you distinguish between similar words Amplified Super Loud Ringer-adjustable ringer volume up to 85db w/ Bright flashing ringer Lighted 2-line LCD screen displays text in bright, large letters Automatically switches between regular calls and Voice Carry-Over (VCO) calls