GoogleVoice (GV for short) is a great service (I won’t go into the details, but you can read up about it here), but it is unfortunately accessible only if you are in the USA.
Granted there is already plenty of documentation about how to circumvent this, but I’m not aware of any of those using Asterisk.

So this post will document how to sign up for a GV account as well as how to use it with Asterisk afterwards, in the prospect of using it if you are not in the USA.

In order to be able to sign up for GV, you need to meet 2 prerequisites :

1. You need to have a US IP address
2. You need to have a US phone number, which will be used to validate your GV account

Step 1 is left as an exercise to the reader (“Good luck ! I’m behind 7 proxies !” :D).

Step 2 is the one we’re going to describe here, as an example of what you can pull with simple Asterisk configurations.