What this means
The IEEE assigned the MA-L block 5C33B1 to EM Microelectronic. 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 5C:33:B1, it is EM Microelectronic hardware.
Frequently Asked Questions
Who owns MAC prefix 5C33B1?
5C33B1 is registered to EM Microelectronic in the IEEE MA-L registry.
What does the MA-L registry type mean?
An MA-L assignment, the IEEE's original OUI format, gives the vendor the first three octets and 16,777,216 device addresses under them. EM Microelectronic's block covers 16,777,216 addresses.
What devices use 5C33B1?
Any network device with a MAC address starting 5C:33:B1 was manufactured by or for EM Microelectronic.