These modems would often slot into a Mini PCI-e slot in the netbook motherboard ... of figuring out which pins are used to talk to the SIM card, and soldering them up to a SIM adapter, or ...

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 ...