A virtual interface bus for portable PCs

There is a growing demand in the automatic test industry for downsized and portable test systems. As a result, laptop and hand held PCs are now becoming more common in the test arena. However, there is a need to standardize and simplify both hardware and software interfaces between the laptop PC, test equipment, and the unit under test. This paper describes the development of a Virtual Interface Bus (VIBus) which consolidates multiple industry standard communication interface protocols into one driver/manager for a laptop or hand held PC application. The development was directed to incorporate the requirements of the IEEE-488, RS-422, Mil-Std-1553, and RS-232 bus protocols into a driver/manager that can be integrated into weapon system test platforms using portable PCs. The successful completion of the project solves two major existing problems: (1) A VIBus software driver/manager allows any of the communication interfaces to be used seamlessly; (2) All of the required interface protocols can be included in a standard laptop PC simultaneously. The solution involves the development of a PCMCIA bus expander that allows many COTS PCMCIA interface cards to be used without removing and replacing cards. The VIBus driver/manager selects the appropriate interface card and drivers as called for by a particular test or data retrieval program, or at the direction of a user.