The Universal Telephone Alert, model UTA-1, is a telephone signal designed for use by individuals who are hard of hearing. This high volume telephone ringer offers four selectable sounds (horn, bell, vibrating chime, or single chime). Volume ranges from 94 to 107 decibels (dB) at three feet (one meter), depending on voltage and sound type selected. The ringer has a 109 dB piezo speaker with tamper resistant volume control, and is equipped with a weather resistant backbox for optional outdoor use. POWER: Uses telephone ringer voltage, 48 volts direct current (DC), 24 volts DC, or 24 volts alternating current (AC).