VME eXtension for Instrumentation: The demand for a compact, both flexible and fast industry-standard instrument-on-a-card architecture has driven the development of the VXI standard. The modular form factor, high bandwidth, and commercial success of the VMEbus made it particularly attractive as an instrumentation platform. The tremendous popularity of GPIB also made it attractive as a model for device communication and instrument control protocols. The VXIbus specification combines VMEbus with GPIB features and covers packaging requirements, electromagnetic compatibility, power distribution, cooling and air flow for VXIbus chassis and plug-in modules. VXI crates and modules come in 2 form factors - C-size (6U x 340mm) or D-size (9U x 340mm). VXI uses the full 32-bit VME architecture, but adds lines for the  instrumentation signals between plug-in module to the outer P2 rows (VME: user defined) and P3 connector of the D-size backplane. Powered VXI chassis for 19" rack installation typically provide 13 slots. In order to be used for sensivite, analog test instrumentation VXI crate power supplies have lowest-noise requirements. offers both C-size and D-szie VXI crates with ultra-low noise power supplies. All crates are modular designed, i.e. consist of the VXI bin, the front-side plug-in fan tray as well as a UEP 6021 power supply which is plugged into the rear. C-size VXI 6021 series  D-size VXI 6021 series