The Mini PCI-e standard has a couple of pins dedicated to USB data lines ... of figuring out which pins are used to talk to the SIM card, and soldering them up to a SIM adapter, or directly ...

Typically available as an external USB module, for desktop computers, the modem may also be available on a PCI or PCI Express (PCIe) card that plugs into an empty slot on the motherboard.

The new Pi offered a number of compelling hardware upgrades, including an onboard PCI-Express interface. The only problem was that the PCIe interface was dedicated to the USB 3.0 controller ...