The Nortel Meridian NT4N65AC is a 2-port Compact Core Network Interface (cCNI) card designed for high-density Nortel Meridian 1 and CS1000 systems. It primarily serves as the critical communication link between the system core (processor) and the network shelves in Option 61C and 81C cabinets. Port Capacity: Features 2 dedicated ports for connecting the system core to network loops.System Role: Acts as the interface that allows the call processor to control and communicate with the peripheral equipment (line and trunk cards) located in the network shelves.Redundancy: In Option 61C and 81C systems, these cards are typically used in pairs across redundant cores to ensure "five-nines" (99.999%) system reliability.Form Factor: Designed as a cPCI (Compact Peripheral Component Interconnect) card for the modernized "Compact Core" architecture. Supported Systems: Specifically engineered for Meridian 1 Option 61C and 81C, as well as Communication Server 1000 (CS1000) large systems.