Nanjing Qinheng Microelectronics holds 14 MA-L blocks under the IEEE registrant "Nanjing Qinheng Microelectronics Co., Ltd.", all carrying the same registered address (No.18, Ningshuang Road, Nanjing, Jiangsu 210012, CN). This is the company that trades as WCH (WinChipHead) — a Chinese fabless IC designer whose parts turn up across an enormous installed base of embedded and DIY hardware. WCH is best known for its CH340/CH341 USB-to-serial bridge chips, which are ubiquitous on Arduino clones and maker boards, but those USB-serial parts do not themselves emit Ethernet MAC traffic and so are not what a WCH OUI represents. The MAC blocks instead back WCH's networking silicon: Ethernet MAC+PHY and protocol-stack chips (e.g. CH394, CH397), UART-to-Ethernet converters with a built-in PHY (CH9120), and Ethernet PHY transceivers (CH182), plus its wireless/Bluetooth microcontrollers. Like Espressif, this is a chipset OUI rather than a finished-brand OUI, but it is reasonably device-class-predictive: a WCH globally-administered address on a network most likely identifies an embedded IoT device, an industrial controller, or a development board built around a WCH Ethernet chip, or a USB-attached network adapter using a WCH NIC chip. The 14-block footprint is consistent with high-volume embedded silicon that needs unique MAC ranges. A closely related registrant, "Jiangsu Qinheng Co., Ltd." (2 additional MA-L blocks at the identical address), is almost certainly a predecessor or alternate legal name and should be cross-linked rather than treated as an unrelated vendor.
- IEEE assignment
- 14 prefixes → "Nanjing Qinheng Microelectronics Co., Ltd." [Confirmed] — IEEE MA-L (verified directly in enrichment/registries/oui.csv; 14 matching rows)
- Registry / block size
- MA-L (24-bit OUI); 14 blocks (~16M addresses each, ~234M total). Count is an exact local-registry figure, not a drifting third-party snapshot. [Confirmed] — enrichment/registries/oui.csv. NOTE: IEEE's public OUI data publishes NO assignment/registration date (oui.csv columns are only Registry, Assignment, Organization Name, Organization Address); any "date registered" on third-party tools (e.g. maclookup.app's per-block dates) is a database artifact, not an IEEE fact, and must not be attributed to IEEE.
- Verified prefixes (all MA-L, this registrant)
- DC:04:5A, 54:14:A7, E0:4E:7A, 0C:3D:5E, 9C:7F:64, 70:19:88, C8:17:F5, 54:6C:50, D0:0C:5E, 50:54:7B, 5C:53:10, 3C:AB:72, DC:32:62, E4:66:E5 [Confirmed] — enrichment/registries/oui.csv
- IEEE registered address
- No.18, Ningshuang Road, Nanjing, Jiangsu 210012, CN (all 14 blocks share this address; the raw oui.csv field has a double space, "Ningshuang Road Nanjing", normalized here) [Confirmed] — enrichment/registries/oui.csv
- HQ / country
- Nanjing, Jiangsu, CN (registry address; also matches the company's stated location) [Confirmed] — enrichment/registries/oui.csv; https://www.wch-ic.com/about_us.html
- Trade name
- WCH (WinChipHead) [Confirmed] — https://www.wch-ic.com/, https://oemdrivers.com/winchiphead
- Company status
- active [Confirmed] — https://www.wch-ic.com/
- Vendor website
- https://www.wch-ic.com/ [Confirmed] — https://www.wch-ic.com/
- Founding year
- Unknown — not stated on the vendor site and no verifiable source found [Unknown]
- Device types
- Ethernet MAC+PHY / protocol-stack chips, UART-to-Ethernet converters, Ethernet PHY transceivers, USB NIC chips, and wireless/Bluetooth MCUs — embedded in IoT, industrial, and consumer devices. (WCH's well-known CH340/CH341 USB-to-serial bridges are NOT what a WCH OUI represents — they do not emit Ethernet MAC traffic.) [Confirmed] — https://www.wch-ic.com/products/CH394.html, https://www.wch-ic.com/products/CH397.html, https://www.wch-ic.com/products/CH182.html
- Notable products
- CH394 (10/100M Ethernet MAC+PHY with built-in TCP/IP stack), CH397 (USB NIC with RISC-V core + 100M Ethernet MAC+PHY), CH9120 (UART-to-Ethernet converter with built-in 10M PHY), CH182 (industrial 10/100M Ethernet PHY); separately the CH340/CH341 USB-serial bridges that are ubiquitous on maker boards [Confirmed] — https://www.wch-ic.com/products/CH394.html, https://www.wch-ic.com/products/CH397.html, https://www.lcsc.com/product-detail/Ethernet-ICs_WCH-Jiangsu-Qin-Heng-CH9120_C2681747.html
- Block-count cross-check
- third-party databases broadly agree — maclookup.app lists 14 blocks, macaddress.io lists 13 (minor sync lag). Local oui.csv is authoritative at 14. [Likely] — https://maclookup.app/vendors/nanjing-qinheng-microelectronics-co-ltd, https://macaddress.io/statistics/company/30519
- Security context
- No CVEs or public security advisories found for Nanjing Qinheng / WCH chips. Absence of CVEs is not a safety guarantee — these are commodity embedded parts across a very broad, largely unmanaged device population. [Likely] — https://nvd.nist.gov/search
- Related vendors
- "Jiangsu Qinheng Co., Ltd." — 2 additional MA-L blocks (38:3B:26, 84:C2:E4) at the same address; likely predecessor or alternate legal name; a distinct registrant string in the IEEE registry. [Confirmed] — enrichment/registries/oui.csv
- Special note
- Chipset OUI, reasonably device-class-predictive. A WCH globally-administered address most likely indicates an embedded IoT device, industrial controller, or dev board using a WCH Ethernet chip (CH394/CH397/CH9120), or a USB network adapter using a WCH NIC chip. [Likely] — https://www.wch-ic.com/products/CH394.html, https://www.wch-ic.com/products/CH397.html
- Analyst note
- Treat a WCH OUI as an embedded/IoT signal for triage; on a corporate network these are commonly unmanaged IoT/industrial endpoints and are candidates for network-segmentation and rogue-device review. Cross-link the "Jiangsu Qinheng" blocks to this entry.