The OPTI-MX Chassis is a 19- or 23-inch rack-mountable platform for the OPTI-MX system. This chassis houses High Speed (HS) modules for terminating fiber circuits of up to OC-12 rate. It houses up to 12 Tributary Modules that can deliver DS3/EC1, DS1, OC-3, and Ethernet services through its mid speed (MS) slots.