> wonder why they chose that form factor instead of like direct-serial Because MiniPCIe is a common formfactor for cellular modems, so this could be swapped in

> wonder why they chose that form factor instead of like direct-serial Because MiniPCIe is a common formfactor for cellular modems, so this could be swapped in to existing devices with no hardware changes and minimal software changes. The slot carries not only a lane of PCIe but also a channel of USB 2.0 and SIM connections. Most cellular modems entirely ignore the PCIe and just use it in USB mode, which I assume this is doing as well. Personally I'd have chosen M.2 as MiniPCIe is outdated, but I also would not at all be surprised to find that the industrial IoT world they're targeting has kept using the deprecated standard because some major vendor got a great deal on MiniPCIe connectors when the mainstream computing world switched to M.2. Considering how many devices designed well after the introduction of MicroUSB or even USB-C I still come across with MiniUSB connectors I feel like that's a common thing in the niche computing device world, intentionally and knowingly making new things using the obsolete connector to save a few cents per unit.