I recently moved and don't currently have a fiber connection, but mobile 5G service is inexpensive and consistently reaches over 100 Mbps, sometimes much more. Wi‑Fi hotspot works on my laptop, but the latency is noticeably worse than on the phone itself. USB tethering gives me much better ping, although the phone's USB-C port is loose and the connection is unreliable. I still have the modem from my previous fiber service and have seen USB-C-to-fiber cables for sale. Could I connect my phone to that modem and use USB tethering as its internet connection, or would I need different hardware?
2 Answers
The easiest option is a dedicated 4G/5G modem-router with a SIM slot. It can use the mobile network directly and provide Ethernet and Wi‑Fi to your devices, without relying on the phone’s loose USB port. Another possibility is a normal router that explicitly supports Android USB tethering, but compatibility varies and many fiber devices cannot do this.
No—the USB-C-to-fiber cables you’re seeing are generally fiber-optic USB extension cables. They don’t convert a phone’s USB tethering connection into the fiber or Ethernet connection that a fiber modem expects. Your old fiber modem won’t normally accept internet this way.
A USB-C-to-Ethernet adapter by itself probably won’t solve it either. The phone would need to provide Ethernet tethering, and the router or modem would need to support that connection as a WAN source.
If you buy anything, look specifically for Android USB-tethering support or a 5G SIM router. A regular fiber ONT/modem is designed for the fiber provider’s signal and usually cannot be repurposed for phone tethering.