Ask a Cell Guru is a weekly column in which our very own CellGuru will answer your questions regarding cellphones, secret codes, service providers and beyond. Have a question for CellGuru? Don't be shy, email itto us!

You ask:

Iv'e been hearing a lot about GSM codes and shortcuts. What exactly are they and how can I use them to divert my calls?

CellGuru answers:

Well! everybody seems to be such great experts when it comes to cellphones, but the GSM subject is definitely something that got left behind on the continuous journey to mobile greatness - so I'm glad you asked about it.

Ok, so first, I'll explain what is GSM. GSM stands for Global System for Mobile communications. It is the most popular standard for mobile phones in the world. Its promoter, the GSM Association, estimates that 82% of the global mobile market uses the standard.

GSM is used by over 2 billion people across more than 212 countries and territories. Its ubiquity makes international roaming very common between mobile phone operators, enabling subscribers to use their phones in many parts of the world. GSM differs from its predecessors in that both signaling and speech channels are digital call quality, and so is considered a second generation (2G) mobile phone system.

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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!

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.

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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]

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