the author of this app says:
With buttons that take up half the screen, you'll have no problem finding the right ones to push. The system is a lot like a phone directory where you push the number on the phone that represents the letter. It will then match up those letters to the name you are looking for and give you the correct extension, and this application is just that much easier to use because of it's friendly interface. Give it a try. It's so simple and quick that I think you'll get addicted.