Which company owns MAC address prefix AC:3F:A4?

MAC address prefix AC:3F:A4 is registered to TAIYO YUDEN CO.,LTD in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with AC:3F:A4 has a network interface built by TAIYO YUDEN CO.,LTD.

What is the OUI AC:3F:A4?

AC:3F:A4 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to TAIYO YUDEN CO.,LTD. It covers every address from AC:3F:A4:00:00:00 to AC:3F:A4:FF:FF:FF, or 16,777,216 addresses in total. It is also written AC-3F-A4.

How do I find the manufacturer of a MAC address?

Take the first three octets of the address — in AC:3F:A4:00:00:00 that is AC:3F:A4 — 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 TAIYO YUDEN CO.,LTD located?

TAIYO YUDEN CO.,LTD is listed at 8-1, Sakae-cho Takasaki-shi Gunma JP 370-8522 in the IEEE OUI registry entry for AC:3F:A4. This is the address the organization registered with the IEEE, which may differ from its current operating address.

How many MAC prefixes does TAIYO YUDEN CO.,LTD own?

TAIYO YUDEN CO.,LTD holds 3 OUI prefixes in the IEEE registry, of which AC:3F:A4 is one. A device made by TAIYO YUDEN CO.,LTD could carry a MAC address from any of them.

TAIYO YUDEN CO.,LTD

MAC address prefix AC:3F:A4 is registered to TAIYO YUDEN CO.,LTD in the IEEE OUI registry. Any device whose MAC address begins with AC:3F:A4 has a network interface built by TAIYO YUDEN 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 AC:3F:A4:00:00:00 to AC:3F:A4:FF:FF:FF.

OUI prefix: AC:3F:A4
Hyphen form: AC-3F-A4
MAC range: AC:3F:A4:00:00:00 – AC:3F:A4:FF:FF:FF
Addresses in block: 16,777,216
Organization: TAIYO YUDEN CO.,LTD
Address: 8-1, Sakae-cho Takasaki-shi Gunma JP 370-8522
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.

Other prefixes from TAIYO YUDEN CO.,LTD

TAIYO YUDEN CO.,LTD holds 3 OUI prefixes in total. A device with this exact prefix could just as well carry any of these:

Assignment history (2)

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

2016-07-29Assigned to "TAIYO YUDEN CO.,LTD"
archived source →
2026-07-17Assigned to "TAIYO YUDEN CO.,LTD"

Nearby in the registry

The prefixes assigned immediately before and after AC:3F:A4:

FAQ

Which company owns MAC address prefix AC:3F:A4?: MAC address prefix AC:3F:A4 is registered to TAIYO YUDEN CO.,LTD in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with AC:3F:A4 has a network interface built by TAIYO YUDEN CO.,LTD.
What is the OUI AC:3F:A4?: AC:3F:A4 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to TAIYO YUDEN CO.,LTD. It covers every address from AC:3F:A4:00:00:00 to AC:3F:A4:FF:FF:FF, or 16,777,216 addresses in total. It is also written AC-3F-A4.
How do I find the manufacturer of a MAC address?: Take the first three octets of the address — in AC:3F:A4:00:00:00 that is AC:3F:A4 — 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 TAIYO YUDEN CO.,LTD located?: TAIYO YUDEN CO.,LTD is listed at 8-1, Sakae-cho Takasaki-shi Gunma JP 370-8522 in the IEEE OUI registry entry for AC:3F:A4. This is the address the organization registered with the IEEE, which may differ from its current operating address.
How many MAC prefixes does TAIYO YUDEN CO.,LTD own?: TAIYO YUDEN CO.,LTD holds 3 OUI prefixes in the IEEE registry, of which AC:3F:A4 is one. A device made by TAIYO YUDEN CO.,LTD could carry a MAC address from any of them.