The TB-2641 terminal block creates a 1-wire 8x64 matrix configuration for the NI PXI-2532.
1-wire configurations are typically used for single-ended signals: when there is a shared or common ground return. In these configurations, the common ground signal line is typically wired externally (not switched).
If a portion of your application requires the switching of differential (2-wire) signals, then you can use an additional column for each signal's ground reference. Similarly, additional rows are required.
If your entire application switches only 2-wire signals, then the TB-2643 or TB-2644 may be more appropriate than the TB-2641.
The TB-2643 terminal block creates a 2-wire 4x64 matrix.
The TB-2644 terminal block creates a 2-wire 8x32 matrix.
Hope this helps!
Switch Product Support Engineer
NI - USA