These modems would often slot into a Mini PCI-e ... USB port. Then, it’s a simple enough matter of figuring out which pins are used to talk to the SIM card, and soldering them up to a SIM ...

All of the adapters below are available as external USB modules as well as PCI or PCI Express (PCIe) cards that plug into an empty slot on the motherboard. See PCI and PCI Express. Cellular ...

Typically available as an external USB module, for desktop computers, the modem may also be available on a PCI or PCI Express ... card" or "broadband card." Generic terms are "broadband adapter ...