Microprocessor based computer terminal

摘要

An apparatus for conducting input output operations with another data processing device in a flexible and low cost manner is comprised of a programmed microprocessor coupled to a keyboard, a parallel port, and a modem. The microprocessor is programmed to periodically scan the keyboard to determine what keys if any are depressed. It also scans the parallel port for incoming data and senses incoming data from the modem by sensing a start bit. Control characters from the keyboard can set options such that incoming data from an input can be simultaneously sent out from the modem and/or parallel port.