Android SMS Gateway Using MQTT

I did something like this 10 years ago. I had a 3G modem with a SIM card and it allowed more than the regular SMS app on your phone. Obviously I didn&#x27;t have a whole app, just a simple CLI.<p>For example, you could send class 0 SMS (flash) with it. The kind of SMS that shows up on your screen, and all you can do is click OK, and it just disappears.<p><a href="https:&#x2F;&#x2F;stackoverflow.com&#x2F;questions&#x2F;5557135&#x2F;sending-fullscreen-disappearing-smss-to-an-iphone" rel="nofollow">https:&#x2F;&#x2F;stackoverflow.com&#x2F;questions&#x2F;5557135&#x2F;sending-fullscre...</a>

Is there something like this but for calls?<p>Make your phone into an SIP&#x2F;VoIP <i>server</i>? So that you can receive and make calls from any&#x2F;many Internet clients while the Android phone with SIM is plugged in at home.

I did something similar 20 years ago. Setup 4 Nokia phones with 4 SIM cards for the 4 different networks in Germany.<p>It was possible to connect them via a serial cable to a linux machine and receive&#x2F;send SMS.<p>Used that to offer a horse betting service: people could bet on horses via complex SMS syntax. It worked, but never made enough money :)

A popular alternative, also selfhosted: <a href="https:&#x2F;&#x2F;github.com&#x2F;vernu&#x2F;textbee">https:&#x2F;&#x2F;github.com&#x2F;vernu&#x2F;textbee</a>

This seems cool and all, but wouldn&#x27;t it likely violate ToS of your carrier by doing something like this -- especially if it gets to be of any appreciable scale?