What this means
The IEEE assigned the MA-L block 504B5B to CONTROLtronic GmbH. 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 50:4B:5B, it is CONTROLtronic GmbH hardware.
Frequently Asked Questions
Who owns MAC prefix 504B5B?
504B5B is registered to CONTROLtronic GmbH 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. CONTROLtronic GmbH's block covers 16,777,216 addresses.
What devices use 504B5B?
Any network device with a MAC address starting 50:4B:5B was manufactured by or for CONTROLtronic GmbH.