The LS-40-DB Bit Synchronizer Daughterboard provides optimal reconstruction of a serial PCM data stream that has been corrupted by noise, phase jitter, amplitude modulation, or base line variations. The all-digital design assures a high performance, consistent product, with excellent reliability and long-term stability. A unique Built-in-Test feature allows performance verification for the Bit Synchronizer to ensure the highest level of operation. Autotest BIT is performed for a short duration on the application of power and tests more than 90% of the Bit Synchronizer components. This test verifies that power is properly applied, verifies that there are no internal bit errors, and performs other tests to ensure that the bit synchronizer is fully operational with status indication of results. Command-test BIT performs the same functions and can be initiated by the user at any time through the Lumistar software when used on Lumistar PC products. The user has the ability to generate internal pseudo-random patterns and calculate internal bit error rates with or without the injection of forced errors. Various status indicators are also available through the software. The Bit Synchronizer also contains a BER reader as well as frame sync pattern indicator