Maximum # of interfaces
8

Maximum channels of simultaneous I/O
With the following configuration of interfaces you can have 96 channels of simultaneous analog input and output:

4-192’s each with AD expansion cards (64 analog ins, 32 analog outs)
4-192’s each with DA expansion cards (64 analog outs, 32 analog ins)

Or, with the following configuration you can have 128 channels of analog input with 64 channels of analog output and 64 channels of digital output:

8-192's each with an AD expansion card