The HD-6409 Manchester Encoder-Decoder (MED) is a high speed, low power device manufactured using self-aligned silicon gate technology. The device is intended for use in serial data communication, and can be operated in either of two modes. In the converter mode, the MED converts Non return-to-Zero code (NRZ) into Manchester code and decodes Manchester code into Nonreturn-to-Zero code. For serial data communication, Manchester code does not have some of the deficiencies inherent in Nonreturn-to-Zero code. For instance, use of the MED on a serial line eliminates DC components, provides clock recovery, and gives a relatively high degree of noise immunity. Because the MED converts the most commonly used code (NRZ) to Manchester code, the advantages of using Manchester code are easily realized in a serial data link.