OnSite Systems, Inc.

Any device whose MAC address begins with 00:13:5C has a network interface built by OnSite Systems, 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

00:13:5C

Organization

OnSite Systems, Inc.

Address

3900 Freedom Circle Santa Clara CA US 95054-1222

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.