At least they do until something goes wrong, and you have to troubleshoot your home network, and then those advanced features ...
In short, when you see SOS on your phone, it means you're not connected to a cellular network. "If you see SOS or 'SOS only' ...
Your router's USB port is convenient, but its unreliability makes it susceptible to a potential security risk. Here's the alternative.
Before we had Raspberry Pis and Beaglebones, the art of putting a Linux system in a small, portable project was limited to router hacking. The venerable WRT54G controlled Internet-connected robots ...