NEC Univerge SV8100/8300 670015 CHS2U-US 6-Slot 19 inch Chassis Cabinet (Refurbished)Key Features: Mfr. Part #: 670015 Compatiable with Univerge 8100 8300 When the CD CP00 US is installed in the first CHS2U US, it is the Controlling Chassis Additional chassis, called Expansion Chassis, can be installed to increase the capacity of the system to meet the customer's business needs The system can be expanded from 104 ports to 512 ports by vertically stacking a maximum of three additional chassis onto the controlling chassis Wall Mountable