This auxiliary electronic ringer operates on any analog line that provides a minimum of 40 volts 20-30 Hz AC ring voltage. Nominal 3 KHz warble provides up to 92 dB SPL at 1 meter. The LPR-1 can be connected via screw terminals or modular RJ-11 jack. A volume control and a 7 foot modular cord are provided. No power supply is required.