I have a ready to use bootable sdcard image for raspberry Pi(built with buildroot). This solution allows you to deploy your raspi and huawei-E173 behind your home router, and access the sms send/receive functionality via google-hangout.

In this setup, you need two google accounts, one for you and second one for your raspi-xmpp-chat-bot. You can have the whole setup up and running within 5minutes. This project is a opensource hosted on github. here are the details: http://albert-david.blogspot.de/2016/01/rbox-remotely-deploy...