Amosense Co., Ltd. — A4:61:77, D0:56:BF (MA-L)

A MAC address beginning with A4:61:77 or D0:56:BF belongs to Amosense Co., Ltd., a South Korean electronics manufacturer, and most plausibly identifies one of the company's Sigfox-connected IoT devices — an asset tracker, a personal-safety alarm button, or an air-quality sensor — though no field report has been found tying either exact prefix to one specific named product.

IEEE's registry (the IEEE MA-L registry) lists both blocks as MA-L (24-bit OUI) assignments under the organization name AMOSENSE, at an address romanized as "Narutu street 56 SEOUL Sucho gu KR 06527" — an imperfect transliteration of a Seocho-gu, Seoul street address. Both are standalone /24 blocks, not sub-allocations of any IEEE-administered shared base; a check of the IEEE MA-M registry and the IEEE MA-S registry for "amosense" returned zero matches in either registry.

Amosense Co., Ltd. is a real, operating company: founded November 2008 as part of the AMO Group (a sibling to, but distinct from, fellow group company Amotech), headquartered in Cheonan with roughly 290 employees as of 2024, and publicly listed on South Korea's KOSDAQ exchange under ticker 357580.KQ. The Cheonan corporate address differs from the Seoul address on file with IEEE — plausibly a separate office used at registration time, not a red flag.

Amosense's own Sigfox Partner Network listing names specific IoT products — the T1 through T8 asset-tracker line, personal-safety buttons (ATOZ, NOVO, MUSE-R, UNO, MARE, MUSE), and the VITO air-quality sensor — and its site hosts documentation for a UWB module built on the NXP SR150 chipset. No search, however, surfaced a device-identification thread or scan report linking A4:61:77 or D0:56:BF to any one of these named products specifically.

No CVE is recorded in the NVD, and no malware or IoT-botnet association is documented for Amosense or its products, as of an August 2026 search — an honest negative, not a certified clean record. As with every IEEE OUI assignment, no registration date is published for either block; any third-party "date registered" shown by a lookup mirror restates the same registry row rather than an IEEE fact.

IEEE assignment

2 MA-L prefixes (A4:61:77, D0:56:BF) → organization name "AMOSENSE" [Confirmed] — the IEEE MA-L registry A46177, D056BF

Registry / block size

MA-L (24-bit OUI) only; no MA-M (the IEEE MA-M registry) or MA-S (the IEEE MA-S registry) blocks found for "amosense" — both existing blocks are standalone, not sub-allocations of a shared IEEE base [Confirmed] — the IEEE MA-L registry, the IEEE MA-M registry, the IEEE MA-S registry

HQ / country (IEEE registry)

"Narutu street 56 SEOUL Sucho gu KR 06527," South Korea — quoted verbatim; an imperfect romanization of a Seocho-gu, Seoul address, not independently corrected [Confirmed] — the IEEE MA-L registry

Cross-registry corroboration

both A4:61:77 and D0:56:BF independently map to "Amosense" in the Wireshark the Wireshark manufacturer database [Confirmed] — the Wireshark manufacturer database

Company identity

Amosense Co., Ltd., South Korean electronics/IoT-device manufacturer, part of the AMO Group (sibling to, but distinct from, fellow group company Amotech); founded 2008-11-01; HQ at 90 4-Sandan 5-gil, Jiksan-eup, Seobuk-gu, Cheonan; ~290 employees as of 2024; classified as semiconductor/related-device manufacturing

[Confirmed] — https://www.emis.com/php/company-profile/KR/Amosense_CoLtd_en_4269384.html

Public listing

KOSDAQ ticker 357580.KQ [Confirmed] — https://finance.yahoo.com/quote/357580.KQ/; reportedly listed since June 2021 [Likely — sourced from a search-result summary, not a directly fetch-verified page]

HQ address discrepancy

the Cheonan corporate address does not match the Seoul/Seocho-gu address on the IEEE registry rows — plausibly a separate R&D/sales office used at OUI registration time, a common and unremarkable pattern, not treated as a red flag on identity [Confirmed discrepancy exists; Likely benign explanation] — the IEEE MA-L registry, emis.com company profile

Company substance verdict

SUBSTANTIAL — an identifiable operating company with product/device context and two independent OUI assignments, not a bare single-OUI shell [Confirmed] — the IEEE MA-L registry, emis.com company profile, partners.sigfox.com

Device types

Sigfox-connected asset trackers (T1-T8: pallet location, livestock monitoring, container security), personal-safety alarm buttons (ATOZ, NOVO, MUSE-R, UNO, MARE, MUSE: movement tracking, workplace safety alerts, child safety), air-quality sensor (VITO); also a UWB module documented on the vendor's own domain, built on the NXP SR150 chipset [Likely — drawn from vendor's own product catalog, not a device-specific field sighting] — https://partners.sigfox.com/companies/amosense-co.-ltd., http://www.amosense.com/pdf/uwb/SR150_QuickStartGuide_V01.pdf

Broader product catalog

antennas, EMI/RF shielding materials, wireless-charging shielding sheets, chip varistors, amorphous-core components, LTCC substrates [Likely — from company-profile search summaries, not vendor-page-verified] — emis.com company profile

Per-prefix product mapping

Unknown which specific product line, if any, maps to either individual prefix; no forum post, scan report, or device-identification thread was found tying A4:61:77 or D0:56:BF to a named real-world device — every web source returning those exact prefixes is an IEEE-registry mirror restating the same registry row

[Unknown] — n/a

Registration date

Unknown — IEEE's the IEEE MA-L registry publishes only Registry, Assignment, Organization Name, and Organization Address columns, no date field; no date is asserted here [Confirmed absence of a date field] — the IEEE MA-L registry

Security context

no CVE is recorded in the NVD, and no malware, IoT-botnet, or Mirai-family association is documented for Amosense or its named products, as of an August 2026 search — an honest negative finding, not a certified clean record [Unknown — absence of findings, not proof of absence of any issue] — n/a

Related vendors

Amotech — a separate, fellow AMO Group company; a distinct legal entity, with no shared OUI registration found under this research pass [Confirmed distinct entities] — emis.com company profile / general AMO Group context

Analyst note

an A4:61:77 or D0:56:BF MAC on a globally-administered address reliably indicates genuine Amosense hardware, most plausibly Sigfox-connected IoT equipment (asset tracker, safety button, or sensor) per the vendor's own product catalog; but no source ties either exact prefix to one confirmed device model, so treat device-type identification as vendor-level, not prefix-confirmed.