The National Instruments PCI-8431/4 is a robust RS485/RS422 serial interface device designed for high-speed communication in industrial automation and control systems. Supporting up to four ports, this interface enables flexible data transfer with a maximum baud rate of 3 Mbps. The PCI-8431/4 is capable of customizing baud rates between 50 b/s and 2 Mb/s through both manual configuration using the Measurement & Automation Explorer (MAX) or Windows Device Manager, and programmatically via the NI-Serial application programming interface (API). This model does not support DMA transfers, and it utilizes FIFO handshaking to manage data flow. With a 128-byte FIFO buffer, the device prevents data loss during high throughput situations by signaling to halt incoming data when necessary, ensuring the CPU can manage processing without interruption. The PCI-8431/4 also supports multiprocessor and hyper-threading technologies, enhancing processing efficiency by allowing simultaneous command handling. This device operates with a power requirement of +5 VDC at 725 mA and features a 10-position modular jack connector for versatile connectivity. It measures 4.2 inches by 5.6 inches, weighing only 0.22 lb. While the PCI-8431/4 will continue to be available for purchase and repairs following its mature status announcement, users can access manuals and documentation for setup and maintenance. For pricing, contact a National Instruments sales representative.