Abstract: This invention consists of a data communications interface that provides the means for an electronic, binary, data processing apparatus, or digital computer, to encode information in a base four format, and to communicate, with other data processing apparatuses, which utilize this invention, by exchanging base four digits, in a serial manner, via a standard data communications medium, such as a telephone line. This invention is composed of a serial communication device (SCD) and a line driver (LD). The SCD converts parallel, binary data to serial, base four data, and visa versa. The LD converts base four voltage levels to signals that are appropriate for the communications medium, and visa versa. A tone, for example, would be an appropriate signal for a telephone line. This invention enables information to be exchanged much more rapidly than is possible with a state of the art system.