EFM Networks

Any device whose MAC address begins with 90:9F:33 has a network interface built by EFM Networks. This prefix (the OUI, or Organizationally Unique Identifier) is assigned by the IEEE and is the first three octets of the address.

OUI prefix

90:9F:33

Organization

EFM Networks

Address

6F, Benposra II 1197-1 Bojeong Giheung Gu Yong In Kyunggi do KR 446913

Source

IEEE OUI registry

Have a full MAC address? Look it up— we'll also tell you if it's a randomized (private) address rather than a real manufacturer prefix.