The National Instruments 781421-15 Matrix Switch Card, also known as the NI 2815B, is a high-density switching solution tailored for the NI SwitchBlock platform. This versatile card supports configurations for matrix switching, making it ideal for automated test systems that require flexible signal routing. It is fully compatible with other NI 2810 series cards, allowing users to build multi-card SwitchBlock systems to meet complex testing demands. The 781421-15 can handle high voltage signal switching with a maximum voltage rating of 100 V (DC and CAT I) and a switching current of 0.25 A per channel, alongside a carry current capability of 0.3 A, delivering a maximum switching power of 3 W per channel, which accommodates various testing applications efficiently.

The card ensures exceptional performance, featuring low DC path resistance of less than 1 Ω when new, excellent isolation exceeding 65 dB at 10 kHz and 50 dB at 100 kHz, and low crosstalk levels, notably -60 dB at 10 kHz. These qualities make it suitable for precision measurements and sensitive applications where noise interference is a concern. With optimized relay operation times of less than 1 ms for up to 8 relays and under 2 ms for 50 relays, the card supports rapid switching necessary for automated test setups. Its relays have an extensive lifespan rated at 2.5 × 10^8 mechanical cycles under no load.

The NI 781421-15 operates with a power consumption of 63 mW per relay, with an overall power limit of 3.9 W per card. Physically, it features 96-position plastic SCSI connectors and a compact form factor measuring 11.2 cm x 1.2 cm x 17.1 cm, weighing 320 grams, facilitating integration into existing testing equipment without significant spatial concerns. The card is designed for environmental durability, operating effectively in temperatures ranging from 0 °C to 55 °C and humidity levels of 10% to 90%. Additionally, it complies with multiple safety and electromagnetic compatibility standards, including IEC 61010-1, UL 61010-1, and EN 61326-1, ensuring reliable operation in industrial settings.