The National Instruments PCI-485/4 is a high-performance serial interface card designed for robust RS-485 communication. This card features four ports that utilize differential signaling, ensuring long-distance transmission with exceptional noise immunity. It supports up to 32 devices on a single line, with the capacity to expand this number through the use of repeaters. The PCI-485/4 inherently manages biasing and provides jumper settings for termination to prevent signal ringing, a common issue in multi-device configurations. The automatic control of the driver facilitates efficient communication over a two-wire link, enabling the driver when data transmission is needed and keeping it enabled for an additional character's transmission duration. Furthermore, the card adapts to various baud rates, accommodating diverse communication needs. It connects via standard 9-pin D-sub connectors, making it compatible with RS-232, RS-422, and RS-485 interfaces, and supports configurable character lengths of 5, 6, 7, or 8 bits, along with multiple parity options. Although the PCI-485/4 has been designated as obsolete by National Instruments, it remains accessible for purchase and repair through Apex Waves. Technical specifications include a maximum transfer rate of 460.8 kb/s, a FIFO size of 64 bytes, and dimensions of 4.2 x 5.8 inches, backed by a 2-3 year warranty. User and maintenance manuals are available for download. For pricing information, please consult a sales representative.