The route switch controller (RSC) card is the main processor card for the server, and it performs the following functions: transfers data as Fast Ethernet or gigabit Ethernet packets encapsulated in proprietary protocol, provides high availability when configured in handover-split mode, boots and reloads software images, provides source clocks used by all server cards and power supplies, extracts an external reference clock from an external E1 or T1 signal through a BNC connector on the front panel, and connects to an external alarm source through a DB-15 serial connector located on the front panel. Install the RSC card in the Cisco AS5850 in either slot 6 or slot 7. The card plugs directly into the backplane.