These high-density basic switch modules are designed for general purpose switching where individual relays can be used to route signals to/from the units under test (UUT), or combined externally to form user-defined configurations. The latter approach allows the same switch module to be used for testing multiple UUTs by simply changing the configuration within a UUT-specific external adapter. Up to 480 individual SPST relays, 300 individual SPDT, or 156 SP4T relays can be accommodated in a double-slot VXIbus card (SMP1200) for maximum density.