The Interface Controller Card (ICC) is a high-capacity network interface engine. The ICC employs a midplane architecture which enables it to connect with a series of I/O modules specific to different network interface requirements. The midplane isolates the unique physical characteristics of each type of connection leaving the ICC to perform all of the signaling and protocol processing independently. There are six I/O modules supporting 4, 8, or 16 network spans. A C-bus enabled, VCO switching platform (VCO/4K Series) with a full complement of ICCs and 16-span I/O modules will support more than 4000 ports.