Perhaps, you live in the United States and would like to monitor a vacation home which has the internet and phone turned off. Or perhaps you live in the UK and would like to send a text to your cell phone when an event occurs.

This device will allow my raspberry pi server: https://www.tindie.com/products/Paulware/raspberry-pi-home-automation-network/ to send texts even when external internet is not provided or in parts of the world (like UK) where internet providers do not offer an email to sms service.

This device requires an unlocked sim-card, and monthly fees will apply. It sends a text much like how a cell-phone sends texts.

It will communicate with the pi through the usb port, and get its power from the usb power supply, so it must be connected via an external powered usb hub.