
HTC Desire 510
1 Find "Fixed Dialing Numbers"
Slide two fingers down the display starting from the top edge of your phone.
Press SETTINGS.
Press SETTINGS.
Press Call.
Press Fixed Dialing Numbers.
2 Turn fixed dialling on or off
Press Enable FDN or Disable FDN (depending on the current setting).
Key in your PIN2 (default is 1111) and press OK.
3 Return to the home screen
Press the home icon to return to the home screen.