The Active Switch APS request: slSonetApsRevertive : Switch back to working line after the Wait-to-Restore interval is over, and failures are cleared. It is the lowest priority. slSonetApsManual : Manual switch causes APS switch unless a request of equal or higher priority is in effect. slSonetApsSignalDefectLow : Switch happened because threshold for 'slSonetApsSigFaultBER' was exceeded. slSonetApsSignalDefectHigh : Same as above, but higher priority. slSonetApsSignalFailureLow : Switch happened because threshold for 'slSonetApsSigDegradeBER' was exceeded. slSonetApsSignalFailureHigh : Same as above, but higher priority. slSonetApsForceSwitch : Forced switch forces hardware to switch the active line even if the other line (could be working line or protection line) is in alarm. slSonetApsLockOut : This is the highest priority switch. This will override all other requests. slSonetApsRemoteRequest : indicates that the local switchover was in response to a remote request to switch. slSonetApsLockOut : indicates that the last switchover to the working occurred because of protection lockout.