The MCM (Management and Control Module) board is used as a fault and clock signalling board on the HiPath 4000 Siemens Communication Server common architecture platform. It is connected to the backplane of the CSPCI shelf. The board features the following control functions: Speed control and regulation for fan trays ALUM (power failure transfer) ALIN (alarm interface) Front reference clock Interfaces: ALUM ALIN Front reference clock Backplane The following three signals from the DSCXL board are routed over this interface: ALUM (Trunkline Switch) NAL (Not urgent Alarm) UAL (Urgent Alarm)