The M840 Series OC-192 Multi-rate Clock Recovery Module provides low jitter clock recovery from NRZ or RZ input data formats. Four data rates, 9.953, 10.3125, 10.664 or 10.709Gb/s may be selected digitally. The input data is amplified by limiting amplifiers. The amplified data is applied to the clock recovery circuitry and provided as an output at a constant level.