T-Mobile, USA

Any device whose MAC address begins with 40:05:89 has a network interface built by T-Mobile, USA. This prefix (the OUI, or Organizationally Unique Identifier) is assigned by the IEEE and is the first three octets of the address.

OUI prefix

40:05:89

Organization

T-Mobile, USA

Address

3625 132nd Ave SE BELLEVUE WA US 98006

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.