Abstract: An apparatus for determining the usage of an optical conductor. The apparatus comprises a non-volatile memory operatively associated with the conductor for storing a cumulative usage value representative of the cumulative usage of the conductor. A device responsive to a parameter of use generates a signal representative of usage of the conductor. A circuit is provided which is responsive to the signal and is operatively associated with the memory for generating from the signal a usage value and then generating from the usage value and cumulative usage value stored in the memory an updated cumulative usage value representative of the total cumulative usage of the conductor, and for replacing the cumulative usage value in the memory with the updated cumulative usage value. The circuit may in addition compare the cumulative usage value to a predetermined value representative of maximum usage.