Which company owns MAC address prefix 4C:55:85?

MAC address prefix 4C:55:85 is registered to Hamilton Systems in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with 4C:55:85 has a network interface built by Hamilton Systems.

What is the OUI 4C:55:85?

4C:55:85 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to Hamilton Systems. It covers every address from 4C:55:85:00:00:00 to 4C:55:85:FF:FF:FF, or 16,777,216 addresses in total. It is also written 4C-55-85.

How do I find the manufacturer of a MAC address?

Take the first three octets of the address — in 4C:55:85:00:00:00 that is 4C:55:85 — 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 Hamilton Systems located?

Hamilton Systems is listed at 3143 Production Drive Fairfield OH US 45014 in the IEEE OUI registry entry for 4C:55:85. This is the address the organization registered with the IEEE, which may differ from its current operating address.

Hamilton Systems

MAC address prefix 4C:55:85 is registered to Hamilton Systems in the IEEE OUI registry. Any device whose MAC address begins with 4C:55:85 has a network interface built by Hamilton 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 4C:55:85:00:00:00 to 4C:55:85:FF:FF:FF.

OUI prefix: 4C:55:85
Hyphen form: 4C-55-85
MAC range: 4C:55:85:00:00:00 – 4C:55:85:FF:FF:FF
Addresses in block: 16,777,216
Organization: Hamilton Systems
Address: 3143 Production Drive Fairfield OH US 45014
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 "Hamilton Systems"
archived source →
2026-07-17Assigned to "Hamilton Systems"

Nearby in the registry

The prefixes assigned immediately before and after 4C:55:85:

FAQ

Which company owns MAC address prefix 4C:55:85?: MAC address prefix 4C:55:85 is registered to Hamilton Systems in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with 4C:55:85 has a network interface built by Hamilton Systems.
What is the OUI 4C:55:85?: 4C:55:85 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to Hamilton Systems. It covers every address from 4C:55:85:00:00:00 to 4C:55:85:FF:FF:FF, or 16,777,216 addresses in total. It is also written 4C-55-85.
How do I find the manufacturer of a MAC address?: Take the first three octets of the address — in 4C:55:85:00:00:00 that is 4C:55:85 — 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 Hamilton Systems located?: Hamilton Systems is listed at 3143 Production Drive Fairfield OH US 45014 in the IEEE OUI registry entry for 4C:55:85. This is the address the organization registered with the IEEE, which may differ from its current operating address.