Which company owns MAC address prefix 18:EF:C0?

MAC address prefix 18:EF:C0 is registered to Sercomm Japan Corporation in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with 18:EF:C0 has a network interface built by Sercomm Japan Corporation.

What is the OUI 18:EF:C0?

18:EF:C0 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to Sercomm Japan Corporation. It covers every address from 18:EF:C0:00:00:00 to 18:EF:C0:FF:FF:FF, or 16,777,216 addresses in total. It is also written 18-EF-C0.

How do I find the manufacturer of a MAC address?

Take the first three octets of the address — in 18:EF:C0:00:00:00 that is 18:EF:C0 — 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 Sercomm Japan Corporation located?

Sercomm Japan Corporation is listed at 8F, 3-1, YuanQu St., NanKang, Taipei 115, Taiwan Taipei TW 115 in the IEEE OUI registry entry for 18:EF:C0. This is the address the organization registered with the IEEE, which may differ from its current operating address.

How many MAC prefixes does Sercomm Japan Corporation own?

Sercomm Japan Corporation holds 2 OUI prefixes in the IEEE registry, of which 18:EF:C0 is one. A device made by Sercomm Japan Corporation could carry a MAC address from any of them.

Sercomm Japan Corporation

MAC address prefix 18:EF:C0 is registered to Sercomm Japan Corporation in the IEEE OUI registry. Any device whose MAC address begins with 18:EF:C0 has a network interface built by Sercomm Japan 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 18:EF:C0:00:00:00 to 18:EF:C0:FF:FF:FF.

OUI prefix: 18:EF:C0
Hyphen form: 18-EF-C0
MAC range: 18:EF:C0:00:00:00 – 18:EF:C0:FF:FF:FF
Addresses in block: 16,777,216
Organization: Sercomm Japan Corporation
Address: 8F, 3-1, YuanQu St., NanKang, Taipei 115, Taiwan Taipei TW 115
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 Sercomm Japan Corporation

Sercomm Japan Corporation holds 2 OUI prefixes in total. A device with this exact prefix could just as well carry any of these:

4C:FB:FE

Assignment history (2)

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

2024-02-15Assigned to "Sercomm Japan Corporation"
archived source →
2026-07-17Assigned to "Sercomm Japan Corporation"

Nearby in the registry

The prefixes assigned immediately before and after 18:EF:C0:

FAQ

Which company owns MAC address prefix 18:EF:C0?: MAC address prefix 18:EF:C0 is registered to Sercomm Japan Corporation in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with 18:EF:C0 has a network interface built by Sercomm Japan Corporation.
What is the OUI 18:EF:C0?: 18:EF:C0 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to Sercomm Japan Corporation. It covers every address from 18:EF:C0:00:00:00 to 18:EF:C0:FF:FF:FF, or 16,777,216 addresses in total. It is also written 18-EF-C0.
How do I find the manufacturer of a MAC address?: Take the first three octets of the address — in 18:EF:C0:00:00:00 that is 18:EF:C0 — 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 Sercomm Japan Corporation located?: Sercomm Japan Corporation is listed at 8F, 3-1, YuanQu St., NanKang, Taipei 115, Taiwan Taipei TW 115 in the IEEE OUI registry entry for 18:EF:C0. This is the address the organization registered with the IEEE, which may differ from its current operating address.
How many MAC prefixes does Sercomm Japan Corporation own?: Sercomm Japan Corporation holds 2 OUI prefixes in the IEEE registry, of which 18:EF:C0 is one. A device made by Sercomm Japan Corporation could carry a MAC address from any of them.