Those USB cellular modem sticks that were so popular a few years ago have become almost unavailable now. While searching for a replacement that is likely to be available over a 10 year lifetime, I found https://simcom.ee/modules/wcdma-hspa/sim5360/
, a multi-band 3G modem with GPS and Glonass; USB, UART, I2C and SPI interfaces; a handful of GPIO lines ...
... and "LUA Script Language" (sic).
It appears that the host can either control the numerous features of the modem by sending AT commands to the device, or can download a Lua script to the device so that it does all the clever stuff itself, so the host does not have to be involved.
Now to find a way to talk to it from a Linux device (Beagle Bone Black) rather than using the Windows-only tools... Linux modem-manager does all the right stuff to make a cellular conne
ction and send and receive texts, but it is not obvious how to download and compile the Lua scripts.