Cisco SC22XX signaling controller provides connection to the SS7 network and the NASs. In addition to SS7 protocol functions, the signaling controller provides system resource management (including keeping track of circuit IDs for ports on the NASs for assigning calls), call control (including originating and terminating call processing/signaling), managing resource availability, usage measurements for accounting and management purposes, and alarms. The signaling controller includes scalable open server, alarm relay unit (ARU), failover controller (or A/B switch), patch panel and serial port expander.Cisco SC2202 is a DC powered signaling controller, which features high availability failover architecture, 2 Sun Netra t hosts (active & standby), NEBS compliant host, 256 MB RAM upgradeable to 2 GB, signaling link I/O cards, alarm relay unit, optional second 10/100 BaseT Ethernet, 7 ft rack, systems integration, installation and acceptance testing.