Rack-and-stack instruments: often a better choice than VXI or PXI systems

Automatic test equipment systems made of mature and robust precision instruments tied together with proven interfaces such as GPIB and Ethernet can provide equal or higher value, lower cost of ownership with much better reliability than backplane-based systems. GPIB (general purpose interface bus) allows for complete computer control of all the instruments in the system using easy-to-learn SCPI (standard commands for programmable instrumentation) programming. Ethernet also gives a lot of flexibility for data networking and databasing and, more recently direct instrument control