EASY-TO-USE PHONE BASE - 3.4-inch high-contrast LCD easily adjusts back and forth for maximum readability. Illuminated keypad & buttons are easily seen in any landline telephone lighting conditionsONE TOUCH TELEPHONE CALL BLOCK - Register up to 250 numbers with one-touch Call Block on base unit & cordless handsets. Compatible with Hearing Aid T-Coil (TIA-1083 Compliant). Optional Range ExtenderENHANCED CORDLESS PHONE SOUND QUALITY - Noise Reduction automatically suppresses background interference while enhancing voice tones for clearer conversation on the base unit & cordless handsetsBUILT-IN BABY MONITOR - A monitoring cordless handset in the baby's room sends an immediate alert to the phone system's base unit and any landline phone or cell phonePOWERFUL PHONE BATTERY BACKUP - With a charged cordless handset in the base unit, Enjoy up to 7 hours of talk time when the power goes out. Power source 120 V AC, 60 Hz