Telephonics Corporation

Any device whose MAC address begins with 00:21:A8 has a network interface built by Telephonics Corporation. This prefix (the OUI, or Organizationally Unique Identifier) is assigned by the IEEE and is the first three octets of the address.

OUI prefix

00:21:A8

Organization

Telephonics Corporation

Address

815 Broad Hollow Road Farmingdale New York US 11790

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.