Setting up Google Voice Voicemail on a T-Mobile phone

Taken from: http://www.entropyfarm.org/things/google-voice-setup-t-mobile/

As with other things on this site, I’m lazy and hate to run into a problem that requries hours of digging through forum posts for a solution. The following is (probably) what you should do if:

• You are on T-Mobile in the USA
• You have an Android phone (this may work with others but I have no idea)
• You have a Google Voice number with voicemail set up already
• You want to use Google Voice as your voicemail instead of T-Mobile’s VM

Setup
If all of the above apply to you, the solution is fairly simple:

1. In a browser, login to your Google Voice account, and click on Settings. In the Voicemail tab, set up your greeting.
2. On your phone, install the Google Voice App.
3. From your phone’s dialer, enter * * 0 0 4 * [Your Google Voice Number] #

That’s it, pretty simple.
To disable forwarding, again from your dialer, dial: # # 0 0 4 #

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