Which company owns MAC address prefix 0C:39:56?

MAC address prefix 0C:39:56 is registered to Observator instruments in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with 0C:39:56 has a network interface built by Observator instruments.

What is the OUI 0C:39:56?

0C:39:56 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to Observator instruments. It covers every address from 0C:39:56:00:00:00 to 0C:39:56:FF:FF:FF, or 16,777,216 addresses in total. It is also written 0C-39-56.

How do I find the manufacturer of a MAC address?

Take the first three octets of the address — in 0C:39:56:00:00:00 that is 0C:39:56 — 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 Observator instruments located?

Observator instruments is listed at Rietdekkerstraat 6 Ridderkerk Zuid Holland NL 2984 BM in the IEEE OUI registry entry for 0C:39:56. This is the address the organization registered with the IEEE, which may differ from its current operating address.

Observator instruments

MAC address prefix 0C:39:56 is registered to Observator instruments in the IEEE OUI registry. Any device whose MAC address begins with 0C:39:56 has a network interface built by Observator instruments. 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 0C:39:56:00:00:00 to 0C:39:56:FF:FF:FF.

OUI prefix: 0C:39:56
Hyphen form: 0C-39-56
MAC range: 0C:39:56:00:00:00 – 0C:39:56:FF:FF:FF
Addresses in block: 16,777,216
Organization: Observator instruments
Address: Rietdekkerstraat 6 Ridderkerk Zuid Holland NL 2984 BM
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 "Observator instruments"
archived source →
2026-07-17Assigned to "Observator instruments"

Nearby in the registry

The prefixes assigned immediately before and after 0C:39:56:

FAQ

Which company owns MAC address prefix 0C:39:56?: MAC address prefix 0C:39:56 is registered to Observator instruments in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with 0C:39:56 has a network interface built by Observator instruments.
What is the OUI 0C:39:56?: 0C:39:56 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to Observator instruments. It covers every address from 0C:39:56:00:00:00 to 0C:39:56:FF:FF:FF, or 16,777,216 addresses in total. It is also written 0C-39-56.
How do I find the manufacturer of a MAC address?: Take the first three octets of the address — in 0C:39:56:00:00:00 that is 0C:39:56 — 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 Observator instruments located?: Observator instruments is listed at Rietdekkerstraat 6 Ridderkerk Zuid Holland NL 2984 BM in the IEEE OUI registry entry for 0C:39:56. This is the address the organization registered with the IEEE, which may differ from its current operating address.