Which company owns MAC address prefix 54:A1:04?

MAC address prefix 54:A1:04 is registered to OPTOWL Co.,Ltd in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with 54:A1:04 has a network interface built by OPTOWL Co.,Ltd.

What is the OUI 54:A1:04?

54:A1:04 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to OPTOWL Co.,Ltd. It covers every address from 54:A1:04:00:00:00 to 54:A1:04:FF:FF:FF, or 16,777,216 addresses in total. It is also written 54-A1-04.

How do I find the manufacturer of a MAC address?

Take the first three octets of the address — in 54:A1:04:00:00:00 that is 54:A1:04 — and look that prefix up in the IEEE OUI registry. If the second-lowest bit of the first octet is set, the address is locally administered (a randomized or private MAC), which belongs to no manufacturer and will not resolve; modern phones and laptops use these by default on each network.

Where is OPTOWL Co.,Ltd located?

OPTOWL Co.,Ltd is listed at 16-1 Shinei-cho, Tsuzuki-ku Yokohama Kanagawa JP 2240035 in the IEEE OUI registry entry for 54:A1:04. This is the address the organization registered with the IEEE, which may differ from its current operating address.

OPTOWL Co.,Ltd

MAC address prefix 54:A1:04 is registered to OPTOWL Co.,Ltd in the IEEE OUI registry. Any device whose MAC address begins with 54:A1:04 has a network interface built by OPTOWL Co.,Ltd. This prefix (the OUI, or Organizationally Unique Identifier) is assigned by the IEEE and is the first three octets of the address — it covers every MAC from 54:A1:04:00:00:00 to 54:A1:04:FF:FF:FF.

OUI prefix: 54:A1:04
Hyphen form: 54-A1-04
MAC range: 54:A1:04:00:00:00 – 54:A1:04:FF:FF:FF
Addresses in block: 16,777,216
Organization: OPTOWL Co.,Ltd
Address: 16-1 Shinei-cho, Tsuzuki-ku Yokohama Kanagawa JP 2240035
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.

Assignment history (2)

The IEEE registry publishes current state only — this is the change record we've kept since we started tracking it daily.

2024-11-20Assigned to "OPTOWL Co.,Ltd"
archived source →
2026-07-17Assigned to "OPTOWL Co.,Ltd"

Nearby in the registry

The prefixes assigned immediately before and after 54:A1:04:

FAQ

Which company owns MAC address prefix 54:A1:04?: MAC address prefix 54:A1:04 is registered to OPTOWL Co.,Ltd in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with 54:A1:04 has a network interface built by OPTOWL Co.,Ltd.
What is the OUI 54:A1:04?: 54:A1:04 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to OPTOWL Co.,Ltd. It covers every address from 54:A1:04:00:00:00 to 54:A1:04:FF:FF:FF, or 16,777,216 addresses in total. It is also written 54-A1-04.
How do I find the manufacturer of a MAC address?: Take the first three octets of the address — in 54:A1:04:00:00:00 that is 54:A1:04 — and look that prefix up in the IEEE OUI registry. If the second-lowest bit of the first octet is set, the address is locally administered (a randomized or private MAC), which belongs to no manufacturer and will not resolve; modern phones and laptops use these by default on each network.
Where is OPTOWL Co.,Ltd located?: OPTOWL Co.,Ltd is listed at 16-1 Shinei-cho, Tsuzuki-ku Yokohama Kanagawa JP 2240035 in the IEEE OUI registry entry for 54:A1:04. This is the address the organization registered with the IEEE, which may differ from its current operating address.