@Maholmire Oh, you mean like a 4G modem, right? You can get those, you can get them as USB dongles, you can order a uConsole ( https://www.clockworkpi.com/uconsole ) and wait several months for it to arrive, they have a 4G modem option.

Don't quote me on this, but my understanding is that it is difficult to get them to do vox, but if you get one that has reasonable drivers, data and SMS work fine under Linux.