Once you grow beyond 6 telephone lines or 16 digital stations you will need to add the Vertical SBX Expansion Cabinet. It provides an additional 3 telephone lines and 16 digital station ports. It accepts one additional 3 line, 8 station card to get to the maximum system configuration of 12 lines and 40 stations.
Unlike the station ports in the Vertical SBX base cabinet, these ports are digital only; they do not support any standard analog phones. As a result the station ports also are wired differently from the base. Please call us for details on wiring if you add this cabinet.