Dual 25G over a Single USB4 Cable
LEKUO DTB3F25 is a USB4 / Thunderbolt to dual-port 25G SFP28 fiber optic network adapter. A device without a PCIe slot (laptop, Mac, mini PC) can connect to a 25G fiber network with a single USB4 cable. The downstream port supports 60W Power Delivery and daisy-chaining of USB4/Thunderbolt devices. It is plug-and-play on Mac (no driver required), and also supports Windows and Linux. Real-world internal network transfer speeds reach approximately 2.75 GB/s, making it suitable for post-production, NAS, data centers, and other high-speed scenarios.
Many users in video post-production and NAS communities face a common dilemma: they want to connect their laptop or Mac to a 25G fiber network, but the host has no PCIe slot, or the mini PC is too difficult to disassemble for expansion. Most 25G fiber NICs on the market are PCIe-based and simply won't fit. USB 10G adapters are a fallback, but they cap out at 10G — too slow for 4K/8K素材 transfers.
The LEKUO DTB3F25 fills this gap by packaging a dual-port 25G fiber NIC as an external USB4 device. As long as your computer has a USB4 or Thunderbolt port, you can plug in and get 25G connectivity — no disassembly, no slot required.
What Is the DTB3F25?
In short: it is a "USB4 to dual-port 25G SFP28 fiber optic network adapter." The upstream side has one USB4 port (compatible with Thunderbolt 3/4/5, 40Gbps), the downstream side has another USB4 port for daisy-chaining USB4/Thunderbolt devices, and the network side has two SFP28 optical ports.
Key Advantages
- 25G without a PCIe slot: For laptops, Macs, and mini PCs, this is a direct benefit — no disassembly, no stacking of docks. One USB4 cable delivers dual optical ports.
- Downstream port with power delivery and daisy-chaining: The downstream USB4 port supports 60W PD output and allows daisy-chaining of USB4/Thunderbolt devices, keeping your desk cleaner.
- Plug-and-play on Mac: macOS recognizes the adapter immediately with no additional drivers; Windows and Linux are also supported.
- Stable under load with external power: The unit includes a dedicated DC power adapter, ensuring stable power during sustained high-load transfers, without relying solely on bus power.
Who Is It For?
- Video post-production: Read and write 4K/8K素材 over a 25G link for smoother timeline playback and faster transcoding.
- NAS enthusiasts: Use the dual SFP28 ports for link aggregation or separate network segments, moving the bottleneck away from the NIC.
- Data center / IT operations: Deploy high-speed networking on PCIe‑less lightweight nodes without disassembly.
- High-frequency trading: The low-latency characteristics of fiber optics suit latency-sensitive applications.
Frequently Asked Questions
Q: Can this be used with laptops and mini PCs?
✅ Yes, as long as the device has a USB4 / Thunderbolt interface.
Q: Do I need to purchase optical modules separately? What devices can the 60W downstream port power?
✅ It can power most Thunderbolt docks, portable drive enclosures, or low-power peripherals. Specific power requirements depend on the device's specifications.
Q: Does it really work on Mac without installing drivers?
✅ Yes, macOS supports plug-and-play with no additional drivers required. Windows and Linux are also supported; installation instructions can be found in the official documentation.
Summary
The LEKUO DTB3F25 is a USB4 / Thunderbolt to dual‑port 25G SFP28 fiber optic network adapter that brings 25G fiber networking to PCIe‑less devices such as laptops, Macs, and mini PCs. With one upstream USB4 port (compatible with Thunderbolt 3/4/5), one downstream USB4 port with 60W PD and daisy‑chaining support, and two SFP28 optical ports, it delivers real‑world internal network speeds of approximately 2.75 GB/s. It is plug‑and‑play on macOS and also supports Windows and Linux. Ideal for video post‑production, NAS high‑speed interconnect, data center deployment, and high‑frequency trading, the DTB3F25 is a practical solution for portable devices needing high‑bandwidth fiber network access.