The Avaya INDeX CPU-V-100 is designed to drive a total of 3 cassettes, but it can not run Link Cassettes or ELC's. As it offers a maximum of four cards, the CPU itself plus 3 others, only the Avaya Index PSU 4 is required to run the system.

The Avaya INDeX CPU-V-100 Central Control Unit is configurable to a maximum of 96 ports (3 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.