Koppar LTE Modem - USB-C phone line for your computer
Show HN: A USB-C LTE modem that gives my computer a phone line
Koppar LTE Modem is an open-hardware 4-layer KiCad board that gives any computer its own phone line over a single USB-C cable. Drop in a nano-SIM and the machine sees three ordinary devices: an LTE network adapter powered by the Quectel EC25-EUX, serial ports for AT commands like caller ID and SMS, and a USB sound card built on the RP2040 that carries call audio through the module's PCM interface. That means your computer can answer calls through a headset, hand them to a script or an AI agent, or fire off a text. The board was designed by Koppar from a one-page spec, fully documented with Gerbers, JLCPCB assembly files, and a candid design review, and released under the CERN Open Hardware Licence. No battery, no screen, no speaker, just one cable and a SIM.
One USB-C cable, and the computer sees three ordinary devices through the on-board USB hub.
- gruez
>Where 2G and 3G are switched off, calls need a module firmware with VoLTE and a carrier that allows it; ask the seller.
This is a huge caveat. OP, does your setup even support VoLTE? Otherwise this might become a brick in a few years as your carrier shuts down 2G/3G, as many carriers around the world have already done
- mcculley
This is great. Apple needs to figure out how to fit one into a 16" MacBook Pro.
- Vaushite
Obviously AI vibed, which means the project probably has never been built and wouldn't work if you built it.
- whalesalad
I’d love one of these as a framework module
- mycall
Will LTE continue to work when 6G rolls out in 3 years?