Technical : Using it: GSM codes

What are GSM Codes?

The GSM standard allows most of the functions to be controlled by entering codes into the keypad of a mobile phone: you can set diverts and the like, accept or reject calls, or even change your PIN code by typing at the keypad.

Unfortunately, not all the codes listed here are enabled by every network. If a code isn't supported, it simply won't work: you won't break anything by trying to use it!

Why bother?

Many (though not all) handsets offer menus to do most of these things, but they vary from handset model to model, and are sometimes hidden by networks who don't want to confuse their users.

If you can use the codes directly, you can also store them in memory, so that you can easily recall and reuse them. For example, you might want to divert all calls to your office phone on a regular basis: from memory, it's just two or three keypresses to set up or cancel such a diversion.

Types of call

You know about voice calls, but there are also fax calls, data calls, ALS (line two) calls and SMS messages. Calls of different types can all have different settings associated, using the relevant "bearer code" as shown in the examples below.

The snags

Some networks don't support all services, so some GSM codes will fail. Others sometimes seem to use their own interpretation of the GSM codes.

If you are having trouble setting call diversion, try ##002#[SEND] and/or ##004#[SEND] to clear all existing diverts first. You probably have to cancel a 'no reply' diversion before you can set another with a different timeout.

Call Divert (all call types)

All
Set: **21*destination#[SEND]
Cancel: ##21#[SEND]
Query: *#21#[SEND]
No Answer
Delay nn seconds: max 30 seconds, in 5 second increments
Set: **61*destination*nn#[SEND]
Cancel: ##61#[SEND]
Query: *#61#[SEND]
Unreachable
Set: **62*destination#[SEND]
Cancel: #62#[SEND]
Query: *#62#[SEND]
Busy
Set: **67*destination#[SEND]
Cancel: ##67#[SEND]
Query: *#67#[SEND]
Cancel All
##002#[SEND]

Divert Voice Calls

All
Set: **21*destination*11#[SEND]
Cancel: ##21*11#[SEND]
Query: *#21*11#[SEND]
No Answer
Delay nn seconds: max 30 seconds, in 5 second increments
Set: **61*destination*11*nn#[SEND]
Cancel: ##61*11#[SEND]
Query: *#61*11#[SEND]
Unreachable
Set: **62*destination*11#[SEND]
Cancel: ##62*11#[SEND]
Query: *#62*11#[SEND]
Busy
Set: **67*destination*11#[SEND]
Cancel: ##67*11#[SEND]
Query: *#67*11#[SEND]

Divert Data Calls

All
Set: **21*destination*25#[SEND]
Cancel: ##21*25 [SEND]
Query: *#21*25#[SEND]
No Answer
Delay nn seconds: max 30 seconds, in 5 second increments
Set: **61*destination*25*nn#[SEND]
Cancel: ##61*25#[SEND]
Query: *#61*25#[SEND]
Unreachable
Set: **62*destination*25#[SEND]
Cancel: ##62*25#[SEND]
Query: *#62*25#[SEND]
Busy
Set: **67*destination*25#[SEND]
Cancel: ##67*25#[SEND]
Query: *#67*25#[SEND]

Divert Fax Calls

All
Set: **21*destination*13#[SEND]
Cancel: ##21*13#[SEND]
Query: *#21*13#[SEND]
No Answer
Delay nn seconds: max 30 seconds, in 5 second increments
Set: **61*destination*13*nn#[SEND]
Cancel: #61*13#[SEND]
Query: *#61*13#[SEND]
Unreachable
Set: **62*destination*13#[SEND]
Cancel: #62*13#[SEND]
Query: *#62*13#[SEND]
Busy
Set: **67*destination*13#[SEND]
Cancel: ##67*13#[SEND]
Query: *#67*13#[SEND]

Divert Line 2 Calls

All
Set: **21*destination*89#[SEND]
Cancel: #21*89#[SEND]
Query: *#21*89#[SEND]
No Answer
Delay nn seconds: max 30 seconds, in 5 second increments
Set: **61*destination*89*nn#[SEND]
Cancel: ##61*89#[SEND]
Query: *#61*89#[SEND]
Unreachable
Set: **62*destination*89#[SEND]
Cancel: ##62*89#[SEND]
Query: *#62*89#[SEND]
Busy
Set: **67*destination*89#[SEND]
Cancel: ##67*89#[SEND]
Query: *#67*89#[SEND]

Call Barring

You use call barring to control what calls can be made or received by your account.

The barring code is specific to the network. Ask your service provider.

Note that Call Barring can't work if call diverts are active, even the autodivert set by the network.

All calls
Set: **330*barring code#[SEND]
Cancel: ##330*barring code#[SEND]
Query: *#330#[SEND]

Outgoing calls
Set: **333*barring code#[SEND]
Cancel: ##333*barring code#[SEND]
Query: *#333#[SEND]

Incoming calls
Set: **35*barring code#[SEND]
Cancel: ##35*barring code#[SEND]
Query: *#35#[SEND]

Outgoing international calls
Set: **331*barring code#[SEND]
Cancel: ##331*barring code#[SEND]
Query: *#331#[SEND]

Outgoing international calls except to home country
Set: **332*barring code#[SEND]
Cancel: ##332*barring code#[SEND]
Query: *#332#[SEND]

Incoming calls when outside home country
Set: *351*barring code#[SEND]
Cancel: #351*barring code#[SEND]
Query: *#351#[SEND]
Cancel All Call Barring
#330*barring code#[SEND]

SMS

There is no provision in the GSM specification for diverting SMS messages

Bar incoming SMS messages
Set: *35*barring code*16#[SEND]
Cancel: #35*barring code*16#[SEND]

Call waiting

Set: *43#[SEND]
Cancel: #43#[SEND]
Query: *#43#[SEND]

Incoming call waiting

Reject: 0 [SEND]
Drop current call and answer: 1 [SEND]
Hold current call and answer: 2 [SEND]

Calling line identity

Outgoing CLI Release (recipient sees your number)
Release: *31# destination [SEND]
Withhold: #31# destination [SEND]
Query default: *#31#[SEND]

Incoming CLI Presentation (you see the caller's number)
Allow: *30#[SEND]
Prevent: #30#[SEND]
Query default: *#30#[SEND]

Dial number from memory

Where nnn is the memory location number
nnn#[SEND]

Change PIN codes

Change Call Barring pin code
**03*oldpin*newpin*newpin#

Change SIM pin code
**04*oldpin*newpin*newpin#

Change SIM pin2 code
**042*oldpin*newpin*newpin#

Unblock SIM pin code
**05*PUK*newpin*newpin#

Unblock SIM pin code
**06*PUK2*newpin*newpin#