The M-982-02 is an integrated circuit precise tone detector for special-purpose use in automatic following of switched telephone calls. The circuit uses lowpower CMOS techniques to provide the complete filtering and control required for this function. The basic timing of the M-982-02 is designed to permit operation with almost any progress tone system.The use of integrated circuit techniques allows the M-982-02 to pack the five filters for call progress following into a single 22-pin DIP or 20-pin SOIC. A 3.58 MHz crystal-controlled time base guarantees accuracy and repeatability. The M-982-02 is an enhanced drop-in replacement for the M-982-01. It has a wider operating voltage range (down to 3V). It has lower power consumption under normal operating conditions. In addition, a powerdown (PD) feature is provided to further reduce power consumption when inactive. It includes a 425 Hz detector to support common international call progress requirement.