Nokia Mobile.

To check the phones Software revision for Nokia Mobile.
On the main screen type *#0000#

To enter in the secret menu in Nokia Phone.
On the main screen type *#92702689# [*#war0anty#]
It will take you to a secret menu where you may find some of the information below:
1. Displays Serial Number.
2. Displays the Month and Year of Manufacture
3. Displays (if there) the date where the phone was purchased (MMYY)
4. Displays the date of the last repair - if found (0000)
5. Shows life timer of phone (time passes since last start)

To restore Factory Settings for Nokia mobile
*#7780# reset to factory settings.

Taking picture without getting noticed.
Turn on/off the "click" sound made by the camera by selecting the 'Silent' profile or by turning warning tones on/off.

Hiding your Mobile/ Cellphone Number
Go to: Menu > Tools > Settings > Call > Send My Caller ID >
'Yes', 'No' or 'Set By Network' to follow the default settings of your home network.
It works only with very few network who provide you facility of “Private Number”

Speed Dialing From Simcard contact (not stored in mobile phonebook)
Type number followed by # then call.
Example: 1# or 2# or 21#