The OPTI-6100 SMX chassis is a 19 or 23" rackmountable platform for OC-3/12/48 SONET STM-1/4 SDH optical multiplexers. The chassis provides two high-speed (HS) slots for terminating fiber circuits of up to OC-48 rate, four mid-speed (MS) slots for tributary modules that can deliver DS1/E1, DS3/E3/EC1, OC-3/12, STM-1 or 10/100/1000 Ethernet services and one system controller module (SCM) slot. The ADTRAN OPTI-6100 delivers all the versatility and functionality that today's service providers need for cost-effective network expansion. This compact, state-of-the-art unit seamlessly integrates with and modernizes existing networks. The OPTI-6100 consolidates discrete optical and multiplexer network elements into one small 2U (3.5-inch) high chassis. Two chassis options are available, the MX (17.5 inches wide) and the SMX (8.5 inches wide). The MX mounts in a standard 19-inch or 23-inch rack. The SMX is wall or rack mountable with the option to mount two units side by side in a 19- or 23-inch rack.