Abstract: A telephone ring detector detects a ring signal voltage from a diverse set of signals transmitted on a telephone line before a complete alternating current ring signal cycle is received. In an exemplary embodiment, the ring detector includes a voltage threshold setting device for establishing a voltage threshold and comparing the ring signal voltage to the voltage threshold to provide an output signal when the ring signal voltage is above the voltage threshold. A pair of zener diodes having a selected voltage value can provide the threshold setting and comparison functions. A microprocessor, including a timer for measuring a time duration of the output signal, outputs a ring detection signal when the time duration exceeds a predetermined time interval value, which is substantially less than a full ring cycle. A line switch responsive to the ring detector is provided to direct communication signals to a telecommunications device.