The National Instruments PCI-4021 Switch Controller, identified by part number 778278-01, is a versatile component designed for integration with a variety of switching modules, including SCXI-1102/B/C, SCXI-1124, and the SCXI-116X family, among others. This controller incorporates an advanced SCXI-based switching system that operates without the need for additional software, facilitating the routing of signals over switches and the excitation of data acquisition and measurement devices. It also provides connectivity to third-party instruments from PCI or PXI slots, enhancing operational flexibility.

The PCI-4021 is typically used in conjunction with high-voltage backplane adapters such as the SCXI-1357 or SCXI-1358, as well as low-voltage options like the SCXI-1362. To effectively utilize this controller with devices such as the SCXI-1102/B/C, users will require specific components including a SH9MD-9MD cable, the NI-4021 installation guide, a compatible SCXI chassis, a computer, the NI-SWITCH driver software, and the appropriate backplane adapter. Installation involves powering off the system, inserting the SCXI module into the chassis as per the installation guide, and establishing the necessary connections, including linking the switch controller with the SCXI module using the SH9MD-MD cable. Once connected, users can power on the system to enable operation. The PCI-4021 is designed to fit seamlessly into a standard PCI slot and is backed by a warranty of two to three years.