The text below describes a HP75000 Series C mainframe. I also have a file describing a HP75000 Series B mainframe. Meanwhile this beast occurred in my lab… This is a large, noisy, but super-flexible VXI solution. All 14xx modules from HP and all older 13xx modules (with adapters) can be used inside this mainframe. HP 75000 in general The HP75000 is a VXI mainframe. A VXI mainframe is a standardized infrastructure where individual measurement devices can be simply plugged in and used.