Prerequisites PC equipped with Microsoft Windows 7 32 Bit and 64 Bit OS, Windows 8.1 32 Bit and 64 Bit OS, 4GB RAM or more. Connected by GPIB, USB, RS232 or LAN to a compatible Tektronix Oscilloscope. VISA (Virtual Instrument Software Architecture) must be installed on the PC for OpenChoice Desktop to work. This version of OpenChoice Desktop requires TekVISA v 4.1.0 or higher to be installed on the PC. Tektronix USB Drivers for THS3000 Series Oscilloscopes must be installed on the PC for OpenChoice Desktop to communicate to these oscilloscopes. OpenChoice Desktop communicates directly to THS3000 series oscilloscopes using Serial Port and does not require VISA.