If you have registered 1638 IDD, you will receive a 1638 IDD Service Number enabling you to make IDD
calls from any touch tone phone, including unregistered ones, giving greater flexibility and convenience
with economical IDD rates.
Note to first-time users:
Your 1638 IDD Service Number must be used with a PIN number. If you have not yet set up a PIN for your
1638 IDD service, please call our Account Management Hotline at 2260 8000 using any of your pre-registered
phone numbers to set your PIN and activate the "Account Password" function.