The Avaya INDeX CPU-V-400 is designed to drive a maximum of 2 cabinets. That is a total of 23 cassettes, but one of those will need to be a link cassette, as the two cabinets will need to be linked. The only link cassettes it takes are the LC-1E0G and the LC-2E4G.

The Avaya INDeX CPU-V-400 Central Control Unit is configurable to a maximum of 416 ports (13 x 32 ports) because each cassette uses one full slot and each slot has the potential to support a maximum of 32 ports. The actual number of ports supported by each slot depends on the configuration of the cassette installed. The number of ports supported by each cassette varies from 2 to 32 depending on the particular device and the configuration required.