For Nokia user's only

*#06# for checking the IMEI (International Mobile Equipment Identity)
*#0000# shows the SW version.
*#3370# - Enhanced Full Rate Codec (EFR) activation. It will automatically restart.
*#3370* - Enhanced Full Rate Codec (EFR) deactivation. It will automatically restart.
*#4720# - Half Rate Codec activation. It will automatically restart
*#4720* - Half Rate Codec deactivation. It will automatically restart
*#746025625# - Sim clock allowed status.
Enhanced Full Rate will give you much better sound quality when you enable it. The new Enhanced Full Rate CODEC adopted by GSM uses the ASELP (AlgebraicCode Excitation Linear Prediction) compression technology. This technology allows for much great voice quality in the same number of bits as the older Full Rate CODEC. The older technology was called LPC-RPE (Linear Prediction Coding with Regular Pulse Excitation). Both operate at 13 kilobits.(but you take up more space on the network, so they can charge you more) - Talk-time is reduced with about 5%

Half Rate will give you bad soundquality, which gives the serviceprovider the opportunity to have more calls on the network, and you might get a lower charge from them. - Will give you 30% longer talk-time.

Sim Clock Stop : *#746025625# apparently only works for 3 minuts.


*#92702689# - takes you to a secret menu with 6 choices
1) shows the serial nr.
2) shows when the cel phone was made mmyy
3) shows when the the cel. phone was purchased mmyy
4) shows how many times the cel. phone has been repaired.
5) makes u capebel of transferring user data if u have the gear for it
6) shows how many houres the phone has been on.

For Nokia user's only :

Imagine your hp battery is low, and you are
receiving an important call,
but what a luck, you don't have a charger!
Don't despair. Do you know that all Nokia phone
comes with reserve battery.
They do! To activate, just key "*3370#" on your hp and your
cell will restart with
this reserve and your battery icon bar will show a 50% incerase in
battery.
This reserve will be charged when you charge your
hp next time round. Try it.