Hardly anyone knows these cell phone codes for special functions

If we want to call someone, we enter the corresponding number into the call field of our smartphone. But this dial pad can also be used for other functions: if you type the correct code combinations of letters and numbers, you will get many hidden accesses. These range from simple device information displays to interventions into the system for change purposes.

But be careful – you should never enter codes randomly, as they may cause irreparable damage. Many codes also vary depending on the provider, device, and operating system. Keys made up of letters and numbers are called USSD, GSM or MMI codes.

Perhaps the most well-known USSD key is “*130#”. This allows you to top up your Swisscom prepaid balance. “#121#” occupies the same role in Salt.

As ‘pcwelt’ wrote, Vodafone users can also get the charges for the last call or SMS shown with ‘*102#’. This means that you can also see the number and time of the call, even if you delete it from the official display list.

iPhone users have a separate switch for this: they can see the latest incoming and outgoing calls using “*646#” according to “giga”. iPhone owners can also set a written SMS to be automatically sent later. To do this, use the code “*Later 2#”.

Smartphone owners can also change their Personal Identification Number (PIN) using the dial pad. For this, Android owners use the combination “**04****” and iOS users “**04***#”.

Depending on the device, the PIN can also be changed using the following entry: «**04*[altePIN]*[neuePin]*[neue Pin]#». In general, however, the PIN can also be changed relatively easily in normal settings.

There are many display options and functional tests, especially for Samsung users. You can use “*#7353#” to check speakers, vibration, camera and touch screen in a quick test. The speaker and microphone function can be tested using “*#*#0283#*#*”. You can perform a GPS test using “*#*#1575#*#*”.

If you want to know the software version on your Samsung device, type “*#1111#”. Using “*#1234#” you can select the firmware version, and you can also reinstall it using “*2767*3855#”.

You can know the number of all calls, used, free storage space as well as the number of your contacts by “*#3282*727336*#”.

If you just want to quickly see your phone number, you can use “*135#” as a Telekom client. You can usually see all your system information by using “*#12580*369*#”.

If you want to reset your cell phone to factory settings, you can do so using the key “*#*#7780#*#*”. If you just want to enter service mode instead, you can get there using “*#*#197328640#*#*”. You can usually find additional abbreviations if you explicitly search for codes for your model and provider.