Loopback > STS Use the Loopback > STS subtab to initiate cross-connect card loopbacks. For a list of ONS nodes and cards that support this subtab, see Maintenance. Item Description STS Shows the Port and STS numbers that are available for a cross-connect card loopback. XC Loopback When checked, initiates a cross-connect card loopback. Apply Applies changes made to the fields in the tab. Reset Cancels any changes to the tab and returns the fields to their last-saved settings. Help Displays context-sensitive help.