Can I replace other vendors' module (for example a digitizer) with a Keysight one?

There are two aspects to consider:

1. Module style – Keysight PXI-H style modules can directly replace all other vendors' PXI style modules, and Keysight PXIe style modules can directly replace all other vendors' PXIe style modules.
2. Software –All Keysight modules ship with IVI compliant drivers. If the user software was written to use all class compliant IVI API calls, then the software should work with little or no modification. Otherwise, it is likely that the customer will need to modify their software to accommodate the new digitizer.