New thin laptops often drop the RJ45, and it’d be really handy to get a low‑latency wired link between two laptops (for LAN gaming, fast file transfers, etc.). What if we made a USB‑C expansion card that can act like phones do — present itself as a network device over USB (USB‑Ethernet) when you connect two machines with a Type‑C cable?
I know it’s a niche use case, but seems neat. I might be missing something or be off-base — is this a sensible idea? Would love feedback.
The USB4 spec supports interdomain connection (i.e. you can achieve laptop-to-laptop networking over USB-C). Certain ports wired to certain Framework Laptop mainboards support USB4 (a couple of examples: FW13 AMD Ryzen AI 300 ports Expansion Card Functionality on Framework Laptop 13 (AMD Ryzen™ AI 300 Series) , FW16 AMD Ryzen 7040 ports Expansion Card Slot functionality on Framework Laptop 16 (AMD Ryzen™ 7040 Series)).
Microsoft’s published info on USB4 interdomain connections: Universal Serial Bus 4 (USB4™) interdomain connections | Microsoft Learn
This also remains true for USB-C ports that are rated Thunderbolt 3 or higher.
Thanks for the explanation. I suspected this already existed but couldn’t find clear info.
you need something named USB Gadget Mode