Which company owns MAC address prefix 08:00:5C?

MAC address prefix 08:00:5C is registered to FOUR PHASE SYSTEMS in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with 08:00:5C has a network interface built by FOUR PHASE SYSTEMS.

What is the OUI 08:00:5C?

08:00:5C is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to FOUR PHASE SYSTEMS. It covers every address from 08:00:5C:00:00:00 to 08:00:5C:FF:FF:FF, or 16,777,216 addresses in total. It is also written 08-00-5C.

How do I find the manufacturer of a MAC address?

Take the first three octets of the address — in 08:00:5C:00:00:00 that is 08:00:5C — 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 FOUR PHASE SYSTEMS located?

FOUR PHASE SYSTEMS is listed at 2001 LOGIC DRIVE SAN JOSE CA US 95124-3452 in the IEEE OUI registry entry for 08:00:5C. This is the address the organization registered with the IEEE, which may differ from its current operating address.

FOUR PHASE SYSTEMS

MAC address prefix 08:00:5C is registered to FOUR PHASE SYSTEMS in the IEEE OUI registry. Any device whose MAC address begins with 08:00:5C has a network interface built by FOUR PHASE SYSTEMS. 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 08:00:5C:00:00:00 to 08:00:5C:FF:FF:FF.

OUI prefix: 08:00:5C
Hyphen form: 08-00-5C
MAC range: 08:00:5C:00:00:00 – 08:00:5C:FF:FF:FF
Addresses in block: 16,777,216
Organization: FOUR PHASE SYSTEMS
Address: 2001 LOGIC DRIVE SAN JOSE CA US 95124-3452
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 "FOUR PHASE SYSTEMS"
archived source →
2026-07-17Assigned to "FOUR PHASE SYSTEMS"

Nearby in the registry

The prefixes assigned immediately before and after 08:00:5C:

FAQ

Which company owns MAC address prefix 08:00:5C?: MAC address prefix 08:00:5C is registered to FOUR PHASE SYSTEMS in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with 08:00:5C has a network interface built by FOUR PHASE SYSTEMS.
What is the OUI 08:00:5C?: 08:00:5C is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to FOUR PHASE SYSTEMS. It covers every address from 08:00:5C:00:00:00 to 08:00:5C:FF:FF:FF, or 16,777,216 addresses in total. It is also written 08-00-5C.
How do I find the manufacturer of a MAC address?: Take the first three octets of the address — in 08:00:5C:00:00:00 that is 08:00:5C — 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 FOUR PHASE SYSTEMS located?: FOUR PHASE SYSTEMS is listed at 2001 LOGIC DRIVE SAN JOSE CA US 95124-3452 in the IEEE OUI registry entry for 08:00:5C. This is the address the organization registered with the IEEE, which may differ from its current operating address.