How to use Tapping settings
You can control some functions of your phone by tapping on the phone
With Tapping settings you can define how the tapping commands work.
Select Menu > Tools > Tapping settings and from the following settings:
Reading SMS messages > On — to enable listening to new messages when you receive them by tapping twice on the upper part of the keypad.
Tapping control — to select whether to control sports mode (Training control) or music playback (Music player) by tapping. To not use tapping commands in either application, select Off.
Also see:
How to use speed dial – Nokia 5500 Sport support
How to change settings – Nokia 5500 Sport support

