Which company owns MAC address prefix B8:38:CA?

MAC address prefix B8:38:CA is registered to Kyokko Tsushin System CO.,LTD in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with B8:38:CA has a network interface built by Kyokko Tsushin System CO.,LTD.

What is the OUI B8:38:CA?

B8:38:CA is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to Kyokko Tsushin System CO.,LTD. It covers every address from B8:38:CA:00:00:00 to B8:38:CA:FF:FF:FF, or 16,777,216 addresses in total. It is also written B8-38-CA.

How do I find the manufacturer of a MAC address?

Take the first three octets of the address — in B8:38:CA:00:00:00 that is B8:38:CA — 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 Kyokko Tsushin System CO.,LTD located?

Kyokko Tsushin System CO.,LTD is listed at 2-25-7 sakado,Takatsu-ku Kawasaki Kanagawa JP 213-0012 in the IEEE OUI registry entry for B8:38:CA. This is the address the organization registered with the IEEE, which may differ from its current operating address.

Kyokko Tsushin System CO.,LTD

MAC address prefix B8:38:CA is registered to Kyokko Tsushin System CO.,LTD in the IEEE OUI registry. Any device whose MAC address begins with B8:38:CA has a network interface built by Kyokko Tsushin System 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 B8:38:CA:00:00:00 to B8:38:CA:FF:FF:FF.

OUI prefix: B8:38:CA
Hyphen form: B8-38-CA
MAC range: B8:38:CA:00:00:00 – B8:38:CA:FF:FF:FF
Addresses in block: 16,777,216
Organization: Kyokko Tsushin System CO.,LTD
Address: 2-25-7 sakado,Takatsu-ku Kawasaki Kanagawa JP 213-0012
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.

2016-07-29Assigned to "Kyokko Tsushin System CO.,LTD"
archived source →
2026-07-17Assigned to "Kyokko Tsushin System CO.,LTD"

Nearby in the registry

The prefixes assigned immediately before and after B8:38:CA:

FAQ

Which company owns MAC address prefix B8:38:CA?: MAC address prefix B8:38:CA is registered to Kyokko Tsushin System CO.,LTD in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with B8:38:CA has a network interface built by Kyokko Tsushin System CO.,LTD.
What is the OUI B8:38:CA?: B8:38:CA is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to Kyokko Tsushin System CO.,LTD. It covers every address from B8:38:CA:00:00:00 to B8:38:CA:FF:FF:FF, or 16,777,216 addresses in total. It is also written B8-38-CA.
How do I find the manufacturer of a MAC address?: Take the first three octets of the address — in B8:38:CA:00:00:00 that is B8:38:CA — 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 Kyokko Tsushin System CO.,LTD located?: Kyokko Tsushin System CO.,LTD is listed at 2-25-7 sakado,Takatsu-ku Kawasaki Kanagawa JP 213-0012 in the IEEE OUI registry entry for B8:38:CA. This is the address the organization registered with the IEEE, which may differ from its current operating address.