*#06# for checking the IMEI (International Mobile Equipment Identity) Information you get from the IMEI:

XXXXXX  XX  XXXXXX  X

    TAC      FAC     SNR      SP

TAC = Type approval code
FAC = Final assembly code
SNR = Serial number
SP = Spare

*#0000# To view Software Version.

*#746025625# [*#sim0clock#]
Checks if the sim clock can be stopped. Sim clock stop is a kind of stand-by mode which will save battery time. This code doesn't work with software version 4.59.

*#92702689# [*#war0anty#] takes you to a secret menu with 6 choices:

1. Displays Serial Number.
2. Displays the Month and Year of Manufacture (0997)
3. Displays (if there) the date where the phone was purchased (MMYY)
4. Displays the date of the last repairment - if found (0000)
5. makes you capebel of transferring user data if you have the gear for it
6. shows how many hours the phone has been on

Latest software version: V 5.36 NSE - 8/9 (24-05-00)

V 5.26 NSE - 8/9 (07-04-00)
V 5.02 NSE - 8/9
V 4.41 NSE - 8/9 (17-08-99)0
V 4.11 (???)
V 3.10 NSE - 8

*3370# -[*EFR0#] Enhanced Full Rate Codec (EFR) activation. It will automatically restart.
#3370# -[#EFR0#] Enhanced Full Rate Codec (EFR) deactivation. It will automatically restart.
xx#        -  xx position in Phone Book

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%

Service Provider Codes (UK)
234-10 Cellnet
234-15 Vodafone
234-30 One2One
234-33 Orange
234-50 Jersey Telecom
234-55 Guernsey Telecom
234-58 Pronto GSM