Which company owns MAC address prefix E4:F3:65?

MAC address prefix E4:F3:65 is registered to Time-O-Matic, Inc. in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with E4:F3:65 has a network interface built by Time-O-Matic, Inc..

What is the OUI E4:F3:65?

E4:F3:65 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to Time-O-Matic, Inc.. It covers every address from E4:F3:65:00:00:00 to E4:F3:65:FF:FF:FF, or 16,777,216 addresses in total. It is also written E4-F3-65.

How do I find the manufacturer of a MAC address?

Take the first three octets of the address — in E4:F3:65:00:00:00 that is E4:F3:65 — 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 Time-O-Matic, Inc. located?

Time-O-Matic, Inc. is listed at 1015 Maple St. Danville IL US 61832 in the IEEE OUI registry entry for E4:F3:65. This is the address the organization registered with the IEEE, which may differ from its current operating address.

Time-O-Matic, Inc.

MAC address prefix E4:F3:65 is registered to Time-O-Matic, Inc. in the IEEE OUI registry. Any device whose MAC address begins with E4:F3:65 has a network interface built by Time-O-Matic, Inc.. 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 E4:F3:65:00:00:00 to E4:F3:65:FF:FF:FF.

OUI prefix: E4:F3:65
Hyphen form: E4-F3-65
MAC range: E4:F3:65:00:00:00 – E4:F3:65:FF:FF:FF
Addresses in block: 16,777,216
Organization: Time-O-Matic, Inc.
Address: 1015 Maple St. Danville IL US 61832
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 "Time-O-Matic, Inc."
archived source →
2026-07-17Assigned to "Time-O-Matic, Inc."

Nearby in the registry

The prefixes assigned immediately before and after E4:F3:65:

FAQ

Which company owns MAC address prefix E4:F3:65?: MAC address prefix E4:F3:65 is registered to Time-O-Matic, Inc. in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with E4:F3:65 has a network interface built by Time-O-Matic, Inc..
What is the OUI E4:F3:65?: E4:F3:65 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to Time-O-Matic, Inc.. It covers every address from E4:F3:65:00:00:00 to E4:F3:65:FF:FF:FF, or 16,777,216 addresses in total. It is also written E4-F3-65.
How do I find the manufacturer of a MAC address?: Take the first three octets of the address — in E4:F3:65:00:00:00 that is E4:F3:65 — 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 Time-O-Matic, Inc. located?: Time-O-Matic, Inc. is listed at 1015 Maple St. Danville IL US 61832 in the IEEE OUI registry entry for E4:F3:65. This is the address the organization registered with the IEEE, which may differ from its current operating address.