What this means
The IEEE assigned the MA-L block A4B197 to Apple, Inc.. 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 A4:B1:97, it is Apple, Inc. hardware.
Frequently Asked Questions
Who owns MAC prefix A4B197?
A4B197 is registered to Apple, Inc. 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. Apple, Inc.'s block covers 16,777,216 addresses.
What devices use A4B197?
Any network device with a MAC address starting A4:B1:97 was manufactured by or for Apple, Inc..