If a customer wants to increase the number of N2280A/N2281A channels, do they have to buy an additional 3499 mainframe and module?

You can install two of the N2280A and/or N2281A modules in the 3499A mainframe. The N2280A and N2281A modules each occupy 2 slots. The total number of channels available in one 3499A mainframe with two N2281A's is 32 (1 x 4 x 4 x 2). There are four 1x4 channels or eight 1x2 channels in a 3499A.

If a customer has a 2-slot 3499B mainframe and they want to add more channels than what is available in one 2-slot module, they would need to buy another 3499A/B/C mainframe.