*#06# to check the IMEI (International Mobile Equipment Identity)

*#0000# shows the software version

*#3370# - Enchanced full Rate Codec (EFR) activation. It will automatically
restart.

*#3370# - Enchanced full Rate Codec (EFR) deactivation
*#4720# - Half Rate Codec activation. It will automatically restart.
*#4720# - Half Rate Codec deactivation

Enchanced 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%

The following codes are the standard GSM codes for various network services.
Most Nokia phones have easier ways to activate them through the menus. Check
the guides for your model.

Call Diverting

All
To Activate: * * 21 * NUMBER # [SEND]
To Cancel: # # 21 # [SEND]
To Check: * # 21 # [SEND]
No Answer
To Activate: * * 61 * NUMBER # [SEND]
To Cancel: # # 61 # [SEND]
To Check: * # 61 # [SEND]
Unreachable
To Activate: * * 62 * NUMBER # [SEND]
To Cancel: # # 62 # [SEND]
To Check: * # 62 # [SEND]
Busy
To Activate: * * 67 * NUMBER # [SEND]
To Cancel: # # 67 # [SEND]
To Check: * # 67 # [SEND]
To Cancel All Call Forwarding # # 002 # [SEND]

Call Barring

Before you can activate these barring services you will need a barring code
from your service provider. Call Barring can not be activated if Call
Forwarding diverts are already in use.

All Calls
To Activate: * 330 * BARRING CODE # [SEND]
To Cancel: # 330 * BARRING CODE # [SEND]
To Check: * # 330 # [SEND]
All Outgoing Calls
To Activate: * 333 * BARRING CODE # [SEND]
To Cancel: # 333 * BARRING CODE # [SEND]
To Check: * # 333 # [SEND]
All Incoming Calls
To Activate: * 353 * BARRING CODE # [SEND]
To Cancel: # 353 * BARRING CODE # [SEND]
To Check: * # 353 # [SEND]
All Outgoing Calls
To Activate: * 33 * BARRING CODE# [SEND]
To Cancel: # 33 * BARRING CODE # [SEND]
To Check: * # 33 # [SEND]
All Outgoing International Calls
To Activate: * 331 * BARRING CODE# [SEND]
To Cancel: # 331 * BARRING CODE # [SEND]
To Check: * # 331 # [SEND]
All Outgoing International Calls Except To Home Country
To Activate: * 332 * BARRING CODE# [SEND]
To Cancel: # 332 * BARRING CODE # [SEND]
To Check: * # 332 # [SEND]
All Incoming Calls
To Activate: * 35 * BARRING CODE # [SEND]
To Cancel: # 35 * BARRING CODE # [SEND]
To Check: * # 35 # [SEND]
All Incoming Calls When Outside Home Country
To Activate: * 351 * BARRING CODE # [SEND]
To Cancel: # 351 * BARRING CODE # [SEND]
To Check: * # 351 # [SEND]
Canceling All Call Barring # 330 * BARRING CODE # [SEND]

Call Waiting
To Activate: * 43 # [SEND]
To Deactivate: # 43 # [SEND]
To Check: * # 43 # [SEND]

Calling Line Identity
Outgoing
To Activate: * 31 # [SEND]
To Deactivate: # 31 # [SEND]
To Check: * # 31 # [SEND]
Incoming
To Activate: * 30 # [SEND]
To Deactivate: # 30 # [SEND]