Disclosed and recited herein are devices, systems, methods, and programs by which data is transmitted and, when receipt of the transmitted data has not been acknowledged, an impulse noise occurrence may be diagnosed at the transmitter based on flag streams associated with data transfer units corresponding to the transmitted data. Characteristics of the impulse noise occurrence may be diagnosed based on, at least, a number of consecutive error bits in at least one of the flag streams associated with the data transfer units corresponding to the transmitted data.