Check the listing for details. National Instruments NI 9870 cRIO Serial Interface Module, 4-Port RS232. Condition: Used. Listed at 395.00 USD. National Instruments 9870 serial interface module. Tested, fully functional, and in excellent physical condition. Please note that this module is for cRIO platform only, it is not compatible with cDAQ. 4-Port, RS232 C Series Serial Interface Module - The NI‑9870 adds RS232 serial ports to CompactRIO systems. The serial ports are accessed directly from the FPGA to offer you flexibility in communicating with serial devices. The module has individual buffers on every port that save FPGA space and simplify programming. The NI‑9870 supports standard start bit, stop bit, and handshaking settings. It uses an external power to provide maximum compatibility and reliability under all serial port conditions. For additional information and resources, use the model name to search the manufacturer's website.