this high quality custom made apc serial cable is the replacement apc part 940-0299a. it is used for apc ups management cards and units. compatible with most apc ups and card units that have a 2.5mm hole (looks like headphone hole). you can use this apc 2.5mm replacement cable to reset apc password or other command. this is the list of compatible apc uninterrupted power supply (ups) cards. note: not all units model are listed. your apc ups unit may not list here but it should still work. apc ups network management card 2 - ap9630 and ap6931. schneider ups network management card 2 with environment monitoring, out of band access and modbus - ap9635h.apc 940-0299a replacement cable for apc network management card 2 with environmental monitoring: ap9630 and ap9631apc 940-0299areplacement cable for schneider network management card 2: ap9635h