This enumerated value decodes the APS protocol command carried in the K1/K2 overhead bytes most recently received from the far-end SONET equipment, such as lockout, forceSwitch, signalFailure, or waitToRestore. Admins use it to see what protection request the remote end is signaling, which is useful for diagnosing a switchover that doesn't match local expectations or for confirming APS protocol negotiation between two devices. For example, if apsRxK1K2 reports signalFailure(4), it tells the admin the far-end device detected a failure and is requesting a protection switch, even if the local working line itself looks healthy.