Which company owns MAC address prefix A4:61:77?

MAC address prefix A4:61:77 is registered to AMOSENSE in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with A4:61:77 has a network interface built by AMOSENSE.

What is the OUI A4:61:77?

A4:61:77 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to AMOSENSE. It covers every address from A4:61:77:00:00:00 to A4:61:77:FF:FF:FF, or 16,777,216 addresses in total. It is also written A4-61-77.

How do I find the manufacturer of a MAC address?

Take the first three octets of the address — in A4:61:77:00:00:00 that is A4:61:77 — 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 AMOSENSE located?

AMOSENSE is listed at Narutu street 56 SEOUL Sucho gu KR 06527 in the IEEE OUI registry entry for A4:61:77. This is the address the organization registered with the IEEE, which may differ from its current operating address.

How many MAC prefixes does AMOSENSE own?

AMOSENSE holds 2 OUI prefixes in the IEEE registry, of which A4:61:77 is one. A device made by AMOSENSE could carry a MAC address from any of them.

AMOSENSE

MAC address prefix A4:61:77 is registered to AMOSENSE in the IEEE OUI registry. Any device whose MAC address begins with A4:61:77 has a network interface built by AMOSENSE. 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 A4:61:77:00:00:00 to A4:61:77:FF:FF:FF.

OUI prefix: A4:61:77
Hyphen form: A4-61-77
MAC range: A4:61:77:00:00:00 – A4:61:77:FF:FF:FF
Addresses in block: 16,777,216
Organization: AMOSENSE
Address: Narutu street 56 SEOUL Sucho gu KR 06527
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 AMOSENSE

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

D0:56:BF

Assignment history (2)

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

2026-02-17Assigned to "AMOSENSE"
archived source →
2026-07-17Assigned to "AMOSENSE"

Nearby in the registry

The prefixes assigned immediately before and after A4:61:77:

FAQ

Which company owns MAC address prefix A4:61:77?: MAC address prefix A4:61:77 is registered to AMOSENSE in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with A4:61:77 has a network interface built by AMOSENSE.
What is the OUI A4:61:77?: A4:61:77 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to AMOSENSE. It covers every address from A4:61:77:00:00:00 to A4:61:77:FF:FF:FF, or 16,777,216 addresses in total. It is also written A4-61-77.
How do I find the manufacturer of a MAC address?: Take the first three octets of the address — in A4:61:77:00:00:00 that is A4:61:77 — 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 AMOSENSE located?: AMOSENSE is listed at Narutu street 56 SEOUL Sucho gu KR 06527 in the IEEE OUI registry entry for A4:61:77. This is the address the organization registered with the IEEE, which may differ from its current operating address.
How many MAC prefixes does AMOSENSE own?: AMOSENSE holds 2 OUI prefixes in the IEEE registry, of which A4:61:77 is one. A device made by AMOSENSE could carry a MAC address from any of them.