Apparatus for detecting the configuration of a communication port.

摘要

A system for detecting the configuration of a communication port includes circuitry for monitoring a communication line of the port. If the line changes digital states it is assumed to be an output line of the port. If the line does not change digital states another circuit attempts to force the line into alternately high and low digital states. If the line can be so forced, it is assumed to be an input line of the port.