An optical communication system comprising: an optical transmission path; a plurality of repeaters (131-1-131-n) coupled to the optical transmission path, each of the plurality of repeaters (131-1-131-n) comprising a high loss loopback, HLLB, path; line monitoring equipment, LME, coupled to the transmission path, the LME being configured to transmit a LME test signal on the optical transmission path and receive a LME loopback data from the optical transmission path in response to the LME test signal; and a processor (202, 204) configured to: compare the LME loopback data to baseline loopback data to obtain a first fault signature; analyze the first fault signature using a first fault classifier to indicate a fault if the first fault signature matches a predetermined fault signature, the first fault classifier being a machine learning algorithm trained using the predetermined fault signature, and report a fault in the system if the first fault classifier indicates the fault, wherein the processor (202, 204) is further configured to: analyze the first fault signature using a second fault classifier to indicate the fault if the first fault signature matches the predetermined fault signature, and report a fault in the system if the first fault classifier and the second fault classifier both indicate the fault. an optical transmission path; a plurality of repeaters (131-1-131-n) coupled to the optical transmission path, each of the plurality of repeaters (131-1-131-n) comprising a high loss loopback, HLLB, path; line monitoring equipment, LME, coupled to the transmission path, the LME being configured to transmit a LME test signal on the optical transmission path and receive a LME loopback data from the optical transmission path in response to the LME test signal; and a processor (202, 204) configured to: compare the LME loopback data to baseline loopback data to obtain a first fault signature; analyze the first fault signature using a first fault classifier to indicate a fault if the first fault signature matches a predetermined fault signature, the first fault classifier being a machine learning algorithm trained using the predetermined fault signature, and report a fault in the system if the first fault classifier indicates the fault, wherein the processor (202, 204) is further configured to: analyze the first fault signature using a second fault classifier to indicate the fault if the first fault signature matches the predetermined fault signature, and report a fault in the system if the first fault classifier and the second fault classifier both indicate the fault. compare the LME loopback data to baseline loopback data to obtain a first fault signature; analyze the first fault signature using a first fault classifier to indicate a fault if the first fault signature matches a predetermined fault signature, the first fault classifier being a machine learning algorithm trained using the predetermined fault signature, and report a fault in the system if the first fault classifier indicates the fault, wherein the processor (202, 204) is further configured to: analyze the first fault signature using a second fault classifier to indicate the fault if the first fault signature matches the predetermined fault signature, and report a fault in the system if the first fault classifier and the second fault classifier both indicate the fault. analyze the first fault signature using a second fault classifier to indicate the fault if the first fault signature matches the predetermined fault signature, and report a fault in the system if the first fault classifier and the second fault classifier both indicate the fault.