TESTO AG
MAC address prefix 00:19:4A is registered to TESTO AG in the IEEE OUI registry. Any device whose MAC address begins with 00:19:4A has a network interface built by TESTO AG. 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 00:19:4A:00:00:00 to 00:19:4A:FF:FF:FF.
- OUI prefix
- 00:19:4A
- Hyphen form
- 00-19-4A
- MAC range
- 00:19:4A:00:00:00 – 00:19:4A:FF:FF:FF
- Addresses in block
- 16,777,216
- Organization
- TESTO AG
- Address
- Testo Straße 1 Lenzkirch Baden-Württemberg DE 79853
- 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 "TESTO AG"archived source →
- 2026-07-17Assigned to "TESTO AG"
Nearby in the registry
The prefixes assigned immediately before and after 00:19:4A:
- Fossil Partners, L.P.00:19:44
- RF COncepts, LLC00:19:45
- Cianet Industria e Comercio S/A00:19:46
- Cisco SPVTG00:19:47
- AireSpider Networks00:19:48
- TENTEL COMTECH CO., LTD.00:19:49
- Sagemcom Broadband SAS00:19:4B
- Fujian Stelcom information & Technology CO.,Ltd00:19:4C
- Avago Technologies Sdn Bhd00:19:4D
- Ultra Electronics - TCS (Tactical Communication Systems)00:19:4E
- Nokia Danmark A/S00:19:4F
- Harman Multimedia00:19:50
FAQ
- Which company owns MAC address prefix 00:19:4A?
- MAC address prefix 00:19:4A is registered to TESTO AG in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with 00:19:4A has a network interface built by TESTO AG.
- What is the OUI 00:19:4A?
- 00:19:4A is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to TESTO AG. It covers every address from 00:19:4A:00:00:00 to 00:19:4A:FF:FF:FF, or 16,777,216 addresses in total. It is also written 00-19-4A.
- How do I find the manufacturer of a MAC address?
- Take the first three octets of the address — in 00:19:4A:00:00:00 that is 00:19:4A — 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 TESTO AG located?
- TESTO AG is listed at Testo Straße 1 Lenzkirch Baden-Württemberg DE 79853 in the IEEE OUI registry entry for 00:19:4A. This is the address the organization registered with the IEEE, which may differ from its current operating address.