Abstract: This application discloses cable length measuring apparatus for accurately determining the length of cable at spaced locations by utilizing at least two sets of measuring devices driven by the cable. Electronic switching means receive the length data from each of the measuring devices and processes that data into a command to a cable length marking means. The circuitry of the switch means automatically determines the most favorable instant to cause switching of the measurements of one of the measuring devices to create the command to the marking device to the other of the measuring devices in order to avoid any damage to the cable's jacket because of the switching between the two measuring devices.