On Tesco mobile if you dial the top up line get to the menu where it ask you for topping up by payment or voucher stay on the line and it will give you the option of calling customer care for FREE also try other O2 codes for Tesco mobile they work.

To check minutes on the Cingular network call *646# and you will recieve a FREE txt message with the remaining minutes. To check balance dial al *225# then send and you will recieve a FREE txt message with the current balance but doesn't work with combined billing.

To access ur voicemail on Telstra via another phone, call ur mobile and when you hear your greeting press * then enter your voicemail pin and press #. You will now be told if u have any messages!

To get you account balance on BSNL Mobile in India press *123# and then press call.

If you are in Indiausing IDEA Pre or Postpaid connection then dial *101# you will get a secret menu that will let you to activate or deactivate any supported Idea package for your mobile.

On wind (Italy), type *123# to see credit balance.

If you call *121# on Mobtel network, you'll ger your credit balance.

To check your credit balance on Beeline call *102#

To view your balance on Dialog GSM for pre-paid only type *#456# and press call.

You can see credit balance at display by dialing *444# for Telenor Pakistan. *111# on Mobilink Pakistan. and *100# on Warid Pakistan.

Hutch GSM: To see your credit balance on the screen, Call *141# .

To view balance on Maxis type *#122#