[konstruktors]

Author of the blog post here. I've used [this SIM800 Raspberry Pi hat](https://www.itead.cc/wiki/RPI_SIM800_GSM/GPRS_ADD-ON_V2.0) and it requires some additional GPIO toggling to enable the modem after a power loss. [Here are the scripts](https://github.com/kasparsd/remote-pine) for doing that and creating the PPP network interface.

The USB modems are nice because you get full control over the modem with the AT commands. I've used the Huawei E173 modem which can be easily unlocked and works great out of the box.