Which company owns MAC address prefix 4C:81:20?

MAC address prefix 4C:81:20 is registered to Taicang T&W Electronics in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with 4C:81:20 has a network interface built by Taicang T&W Electronics.

What is the OUI 4C:81:20?

4C:81:20 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to Taicang T&W Electronics. It covers every address from 4C:81:20:00:00:00 to 4C:81:20:FF:FF:FF, or 16,777,216 addresses in total. It is also written 4C-81-20.

How do I find the manufacturer of a MAC address?

Take the first three octets of the address — in 4C:81:20:00:00:00 that is 4C:81:20 — 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 Taicang T&W Electronics located?

Taicang T&W Electronics is listed at 89# Jiang Nan RD Suzhou Jiangsu CN 215412 in the IEEE OUI registry entry for 4C:81:20. This is the address the organization registered with the IEEE, which may differ from its current operating address.

How many MAC prefixes does Taicang T&W Electronics own?

Taicang T&W Electronics holds 45 OUI prefixes in the IEEE registry, of which 4C:81:20 is one. A device made by Taicang T&W Electronics could carry a MAC address from any of them.

Taicang T&W Electronics

MAC address prefix 4C:81:20 is registered to Taicang T&W Electronics in the IEEE OUI registry. Any device whose MAC address begins with 4C:81:20 has a network interface built by Taicang T&W Electronics. 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:81:20:00:00:00 to 4C:81:20:FF:FF:FF.

OUI prefix: 4C:81:20
Hyphen form: 4C-81-20
MAC range: 4C:81:20:00:00:00 – 4C:81:20:FF:FF:FF
Addresses in block: 16,777,216
Organization: Taicang T&W Electronics
Address: 89# Jiang Nan RD Suzhou Jiangsu CN 215412
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 Taicang T&W Electronics

Taicang T&W Electronics holds 45 OUI prefixes in total. A device with this exact prefix could just as well carry any of these:

Assignment history (2)

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

2017-09-08Assigned to "Taicang T&W Electronics"
archived source →
2026-07-17Assigned to "Taicang T&W Electronics"

Nearby in the registry

The prefixes assigned immediately before and after 4C:81:20:

FAQ

Which company owns MAC address prefix 4C:81:20?: MAC address prefix 4C:81:20 is registered to Taicang T&W Electronics in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with 4C:81:20 has a network interface built by Taicang T&W Electronics.
What is the OUI 4C:81:20?: 4C:81:20 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to Taicang T&W Electronics. It covers every address from 4C:81:20:00:00:00 to 4C:81:20:FF:FF:FF, or 16,777,216 addresses in total. It is also written 4C-81-20.
How do I find the manufacturer of a MAC address?: Take the first three octets of the address — in 4C:81:20:00:00:00 that is 4C:81:20 — 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 Taicang T&W Electronics located?: Taicang T&W Electronics is listed at 89# Jiang Nan RD Suzhou Jiangsu CN 215412 in the IEEE OUI registry entry for 4C:81:20. This is the address the organization registered with the IEEE, which may differ from its current operating address.
How many MAC prefixes does Taicang T&W Electronics own?: Taicang T&W Electronics holds 45 OUI prefixes in the IEEE registry, of which 4C:81:20 is one. A device made by Taicang T&W Electronics could carry a MAC address from any of them.