Input/Output Bus Interface Background of the Invention

This invention relates in general to interfaces for computers and particularly to a means of passively gaining access to signals of an Input/Output bus of a ROLM computer. Several models of ROLM computer systems, particularly models 1666B and 1666D provide tactical data management with many military and scientific applications. Passive testing of certain digital signals generated on the I/O bus is desired to ensure proper performance of the computer hardware and software without interfering with its normal operations. An interface is needed to enable a signal monitoring system to gain access to these signals while maintaining the continuity of the interrupt and data channel control lines. An object of the invention is to minimize the noise introduced on the I/O bus when interfacing with a signal monitoring system. Another object is to provide electrical isolation between the I/O bus and a signal monitoring system. A further object is to eliminate the constant need to enter the computer to remove or insert circuit cards when access to I/O bus signals is desired. Keywords: Patent applications. (KR)