Arris 720921 Cadant C3 CMTS 1x4, Arris ARCT00480 Arris C3 2x Upstream ports. Overview The ARRIS C3™ Cable Modem Termination System is a CableLabs® DOCSIS® 2.0 Qualified Cable Modem Termination System (CMTS) delivering superior performance for up to 3000 registered cable modems while occupying only one rack unit (1RU) of space (1.75 in) in a cable operator’s head-end facility. This small size allows operators successful deployments of next generation IP services in both new and existing cable networks in any size market worldwide. The system utilizes a dual RISC processor architecture for supporting high traffic volume with excellent latency control and ample reserve processing resources. Transmit and receive capacity is scalable with a single system supporting one downstream RF channel via an integrated upconverter and up to six upstream RF channels. The two network interfaces support 10/100/1000 BaseT Ethernet.