T320 Standard Control Board Description
Each standard control board consists of the following components:
10/100Base-T/TX Ethernet switch for intermodule communication.
PCI bus to the Routing Engines.
Switch processor mezzanine board (SPMB).

The standard control board faceplate includes the following:
Three LEDs that indicate the status of the control board. T320 Standard Control Board and T-CB LEDs describes the functions of the control board LEDs.
The control board online/offline button. This button is not functional.
One Ethernet port. This port is not used in a T320 router.