This is an ASRock D89 Serial Cable, part number 14G000006530AK. It is designed for use with ASRock SPC621D8-2L2T motherboards and comes in a brown box. This cable facilitates serial communication for your system.
14G000006530AK - Asrock Cable 14G000006530AK D89 Serial Cable for SPC621D8-2L2T Brown Box