What this means
The IEEE assigned the MA-L block 9CA3A9 to Guangzhou Juan Optical and Electronical Tech Joint Stock Co., Ltd. Every network interface they manufacture under this block has a MAC address beginning with these digits, followed by a unique per-device identifier. If a device on your network shows a MAC starting 9C:A3:A9, it is Guangzhou Juan Optical and Electronical Tech Joint Stock Co., Ltd hardware.