Holtek Semiconductor Inc.

Any device whose MAC address begins with 04:AC:44 has a network interface built by Holtek Semiconductor Inc.. This prefix (the OUI, or Organizationally Unique Identifier) is assigned by the IEEE and is the first three octets of the address.

OUI prefix

04:AC:44

Organization

Holtek Semiconductor Inc.

Address

No.3, Creation Rd. II, Science Park Hsinchu TW 300

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.