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How to Use GSM Codes on Your iPhone

Want to feel like a secret service agent? Try using GSM codes on your iPhone, they will remind you of the glorious era of command line interfaces and Bond movies with six digit security codes. Your iPhone is able to interpret so-called GSM codes to perform hidden functions. Here’s a guide on how to use GSM Codes and access hidden features on your iPhone.

What are GSM Codes?

A typical GSM code is made up of numbers, hash symbols (#) and stars (*) and allows you to access hidden settings and features on a cellphone. These features are typically hidden from plain sight and not accessible through regular settings menus. GSM codes are entered through the “Phone” app and submitted as a command by pressing the “Call” button, as if you were calling a number.

Note: It is quite possible that not all of the codes listed on this page will work on your iPhone. This is due to differences across cell providers.

How to enter a GSM Code

Phone > Numberpad

Open up the “Phone” app on your iPhone and simply enter the code through the number pad on your dialer. All of the below codes can be entered through the keypad. The star symbol (*) is found in the bottom left, while the hash (#) can be found in the bottom right. Some of these codes, not all of them, need to be confirmed by “calling” via the “call” button.

The most important GSM codes

  • *#06# – This code will display the so-called IMEI, your international mobile equipment identity. This is needed to check whether an iPhone is activation locked.
  • *135# – This will display your cell number on some networks.
  • *3001#12345#* – This code launches the Field Test App, which we’ve detailed in another article.
  • *#5005*7672# – Enter this code to find out your SMSC number. The SMSC is the service center which relays your SMS messages.
  • *#746025625# – This code will reveal whether your SIM card supports the power-saving “SIM clock” feature.
  • *646# – Not supported by all networks, will display your current call duration volume.
  • *3370# – It is often claimed that this code improves sound quality for regular calls, but we have yet to find it working for us. Quits with an error message.
  • *4720# – This is claimed to be a way of improving your battery life for calls. Similarly to its counterpart, we weren’t able to see it working.
  • *31# [number you are calling] – This code will display your caller id to the other side, irrespective of other settings.
  • #32# [number you are calling] –This code will hide your caller id from the other side, irrespective of other settings.