The OUI prefix 6C:DD:EF is registered to "EPCOMM Inc." at 31072 San Antonio Street, Hayward, CA 94544, US — an MA-L (24-bit) block spanning roughly 16 million MAC addresses. The registration is confirmed first-hand against the IEEE-sourced registry (oui.csv, line 834) and corroborated by two independent MAC-vendor lookup services, so the assignment itself is solid. Everything beyond the assignment is thin: EPCOMM Inc. has no detectable active website (epcomm.com is a parked GoDaddy for-sale page as of June 2026; epcomm.net is unreachable), no published product catalog, and no third-party device sightings tied to this prefix, so the device category is genuinely Unknown rather than asserted. A naming caution matters here for anyone enriching this vendor: EPCOMM Inc. (Hayward, CA) must not be conflated with EPCOM (a Mexico/US security-and-communications distributor at epcom.net), East Point Communication Technology Co. Ltd. (a China-based fiber-optic OEM/ODM at epcom-cnt.com), or Epcom Global Networks (a US ISP operating AS26893) — none of those entities is the registered OUI holder. The holder appears to be a small or now-inactive US company. Per IEEE policy, no registration date is published for this or any OUI block; a "July 7, 2021" timestamp surfaced by one lookup tool is a third-party database artifact, not an IEEE fact, and is recorded as Likely only.
- IEEE assignment
- 6C:DD:EF → EPCOMM Inc., 31072 San Antonio Street, Hayward, CA 94544, US [Confirmed] — IEEE oui.csv (enrichment/registries/oui.csv, line 834); corroborated by https://maclookup.app/macaddress/6cddef and https://udger.com/resources/mac-address-vendor-detail?name=epcomm_inc
- Registry / block size
- MA-L (24-bit OUI), ~16 million addresses [Confirmed] — IEEE oui.csv; https://maclookup.app/macaddress/6cddef
- HQ / country
- 31072 San Antonio Street, Hayward, CA 94544, United States (registry address) [Confirmed] — IEEE oui.csv; https://maclookup.app/macaddress/6cddef
- Company status
- no active web presence — epcomm.com is a parked/for-sale GoDaddy domain, epcomm.net unreachable (as of June 2026); appears small or inactive [Likely] — https://epcomm.com/
- Device types
- Unknown — no product catalog, device line, or third-party device sighting for this prefix is publicly documented; the MA-L block size is consistent with networking/communications hardware but no source corroborates a specific category [Unknown] — https://maclookup.app/macaddress/6cddef
- Registration date
- NONE published by IEEE. A "July 7, 2021" date appears on maclookup.app but is a third-party database artifact, not an IEEE-published fact [Likely] — https://maclookup.app/macaddress/6cddef
- Security context
- no CVEs, advisories, or exploit reports found for EPCOMM Inc. or the 6C:DD:EF prefix; absence reflects lack of public documentation, not a confirmed clean record [Unknown] — no source
- Naming disambiguation
- distinct from EPCOM (epcom.net, MX/US distributor), East Point Communication Technology Co. Ltd. (epcom-cnt.com, China fiber OEM/ODM), and Epcom Global Networks (US ISP, AS26893); none matches the Hayward, CA OUI holder [Confirmed] — https://www.epcom.net/, https://www.epcom-cnt.com/, https://ipinfo.io/AS26893
- Analyst note
- the OUI is a legitimate US registration, but with no website, no product line, and no device sightings, 6C:DD:EF identifies the registrant in name only — treat device-type inferences as unsupported.