National Instruments 779808-01 Multifunction I/O Device 

National Instruments part number 779808-01 is an identifying part number for the USB-6221, a Multifunction I/O Device. It can be configured with 8 differential analog input channels, offering flexible connectivity. The device also features 2 analog output channels and 24 digital I/O lines. Both analog input and output can sample data at up to 250 kS/s. This device includes features such as correlated digital I/O, analog I/O, digital triggering, and two 32-bit timers, making it suitable for various applications like manufacturing tests, laboratory automation, design testing, and research. 

The NI 779808-01 can perform high-voltage measurements when used with compatible signal conditioning accessories (SCC or SCXI). Its digital I/O lines support pulse-width modulation for controlling devices such as lamps, pumps, valves, fans, and motors, with the ability to drive 24 mA signals. The device offers several I/O connectivity options. For PCI/PXI, it has a single 68-pin VHDCI connector. The USB Screw Terminals version comes with 64 screw terminals, while the USB BNC connector type includes 20 BNC connectors and 30 screw terminals. 

The device features an output FIFO with a size of 8,191 samples, which are shared among the channels in use. Data transfers are handled via PCI/PXI DMA (scatter-gather), interrupts, and programmed I/O, while USB data transfers utilize USB Signal Stream and programmed I/O. For analog output, the device supports non-periodic waveforms and periodic waveform regeneration from the onboard FIFO. It also offers periodic waveform regeneration from the host buffer, with the ability for dynamic updates. National Instruments has declared obsolete status for the part number 779808-01, however, it is still available for purchase and repairs at the Apex Waves website.