To connect your smartphone or other devices to the car's network, powered by AT&T in the US, you simply select the network on your mobile device and enter the pin number.
This feature is especially valuable because it helps give your data plan a rest and also allows you to have a connection wherever you go. There's a free trial period when you begin using OnStar, and data plans otherwise start at $10/1GB per month.
In addition, you can push the OnStar button at anytime if you need roadside assistance. The OnStar service will also automatically notify emergency services if you are in an accident