What happens if you dial star-89 on your home phone?

In the United States, *89 is the code to cancel call return. If you dial *69, the phone system will attempt to call back the last person who called you, and will continue to try until either the call goes through or you dial *89 to cancel.

If you have a rotary or pulse-dial phone, you can dial 11xx instead of *xx for any of the "star codes" (vertical service codes).