SEMAPHORE COMMUNICATIONS CORP.

Any device whose MAC address begins with 00:C0:5A has a network interface built by SEMAPHORE COMMUNICATIONS CORP.. 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:C0:5A

Organization

SEMAPHORE COMMUNICATIONS CORP.

Address

217 HUMBOLDT COURT SUNNYVALE CA US 94089-1300

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.