Data communication interface integrated circuit with data-echoing and non-echoing communication modes

摘要

An integrated circuit communication interface device includes data bus terminals, a serial output terminal, a serial input terminal, and an internal data bus. A data bus buffer connects the data bus terminals to the internal data bus. A transmit buffer connects the serial output terminal to the internal data bus. A receive buffer connects the serial input terminal to the internal data bus. Control circuitry controls the buffer so that the device receives or transmits data in either the Echoplex protocol or the RS 232 protocol. The device includes a data register which is programmed to select the device's mode of operation.