Which company owns MAC address prefix EC:42:B4?

MAC address prefix EC:42:B4 is registered to ADC Corporation in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with EC:42:B4 has a network interface built by ADC Corporation.

What is the OUI EC:42:B4?

EC:42:B4 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to ADC Corporation. It covers every address from EC:42:B4:00:00:00 to EC:42:B4:FF:FF:FF, or 16,777,216 addresses in total. It is also written EC-42-B4.

How do I find the manufacturer of a MAC address?

Take the first three octets of the address — in EC:42:B4:00:00:00 that is EC:42:B4 — 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 ADC Corporation located?

ADC Corporation is listed at 77-1, Miyako Namegawa-machi, Hiki-gun Saitama Pref. JP 355-0812 in the IEEE OUI registry entry for EC:42:B4. This is the address the organization registered with the IEEE, which may differ from its current operating address.

ADC Corporation

MAC address prefix EC:42:B4 is registered to ADC Corporation in the IEEE OUI registry. Any device whose MAC address begins with EC:42:B4 has a network interface built by ADC Corporation. 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 EC:42:B4:00:00:00 to EC:42:B4:FF:FF:FF.

OUI prefix: EC:42:B4
Hyphen form: EC-42-B4
MAC range: EC:42:B4:00:00:00 – EC:42:B4:FF:FF:FF
Addresses in block: 16,777,216
Organization: ADC Corporation
Address: 77-1, Miyako Namegawa-machi, Hiki-gun Saitama Pref. JP 355-0812
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.

2017-09-08Assigned to "ADC Corporation"
archived source →
2026-07-17Assigned to "ADC Corporation"

Nearby in the registry

The prefixes assigned immediately before and after EC:42:B4:

FAQ

Which company owns MAC address prefix EC:42:B4?: MAC address prefix EC:42:B4 is registered to ADC Corporation in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with EC:42:B4 has a network interface built by ADC Corporation.
What is the OUI EC:42:B4?: EC:42:B4 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to ADC Corporation. It covers every address from EC:42:B4:00:00:00 to EC:42:B4:FF:FF:FF, or 16,777,216 addresses in total. It is also written EC-42-B4.
How do I find the manufacturer of a MAC address?: Take the first three octets of the address — in EC:42:B4:00:00:00 that is EC:42:B4 — 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 ADC Corporation located?: ADC Corporation is listed at 77-1, Miyako Namegawa-machi, Hiki-gun Saitama Pref. JP 355-0812 in the IEEE OUI registry entry for EC:42:B4. This is the address the organization registered with the IEEE, which may differ from its current operating address.