The Craft interface is a small panel which provides a physical and visual interface to the router, primarily featuring the Serial console ports, and Management Ethernet ports, LED indicators, and Alarm indicators. Depending upon the router model, the Craft interface may also have an LCD screen which can display information about the status of the router.
Alarm LEDs indicate the level of an alarm if one has occurred. The Craft interface also has two alarm relay contacts, which can be used to trigger an external alarm in the event of a Yellow or Red router Alarm. Red alarms indicate a serious condition in which service interruption could occur, such as a critical component failure. Yellow alarms indicate recoverable errors, maintenance alerts, or failures of non-critical components.