National Instruments 781745-01 Serial Interface Device 

National Instruments part number 781745-01 is an identifying part number for the PCIe-8433/2 Serial Interface Device. The NI 781745-01 is a 2-Port Device based on the PCI Express platform. It supports two protocols: RS-422 and RS-485. The device has a male DB-9 connector. It provides 60 VDC (CAT I) continuous isolation both Port-to-Port and Port-to-Host. This Serial Interface can handle surge voltages up to 2000 Vrms. It supports DMA transfers, offering faster performance compared to other products. 

This device is compatible with multiprocessor and multithreading PCs and features 128 B FIFOs for precise data transmission and reception. It also works with RS485 and Modbus-based serial PLCs. This model draws power directly from the PCI Express channel, so no additional power supply is needed. Typically, it requires 140 mA from the +12 VDC rail and 610 mA from the +3.3 VDC rail. However, it can draw up to 240 mA and 660 mA from these voltage levels at maximum. The device can operate in both 2-wire and 4-wire transceiver modes, allowing users to choose between half-duplex and full-duplex communication. 

It measures 4.38 × 6.6 inches, making it easy to install in any available PCIe slot in a computer. The installation process for part number 781745-01 is the same as for other serial interface modules. First, power down the computer and install your serial PCI Express hardware. Then, power the computer back on. Once Windows detects the new hardware, open the NI-Serial Troubleshooter. The NI-Serial Troubleshooter window will appear, and the application will check both the software and hardware installations, testing each NI serial port in sequence. After this, connect the necessary cables.