3Com NBX Voice Mail Upgrade/ 20 Port (3C10327)\\nAftermarket SS3 NBX upgrade for 20 automated attendant (AA) ports. This is a unit-based license that adds twenty incremental ports to the existing voicemail ports installed on the system. Provides a license key-code to activate functionality. Operates on Ss3 NBX R4.1 system software and greater and NBX V3000 only. SS3 NBX can support up to 72 AA ports. NBX V3000 supports up to 12 AA ports with base configuration and up to 72 AA ports if upgraded with 512MB memory module (3C10240).