Supplementary service codes

GSM USSD codes are service and control commands in the GSM mobile network, which Symbol-/Zeichenfolgen of arrow keys, numbers, hash marks ( #), and asterisks (* ), which are stored on each keyboard and by concluding with the " green phone be " discontinued. By entering these combinations various settings in the active network and on the SIM card can be changed. The user can thus configure its wireless connection individually, especially redirects and the behavior of the mailbox.

USSD codes work on any mobile phone from the same - a significant advantage over the control of the same functions from the command menu: The menu of many mobile phones are different. In addition, menu items allow not always use all GSM functions that are accessible via code. What services and settings can be changed in the network is determined by the activation profile of the card; these vary depending on the network operator.

Postpaid and prepaid cards make a difference. These codes are linked to a dedicated GSM service in the HLR, which was activated configurable or fixed. This usually leads to the fact that prepaid customers neither " Call Waiting" can use to set the " ring time extension " because the diversion is permanently set on the answering machine for most mobile network operators.

Code table

It should be noted that in some mobile phones, the following commands are sent already with the final hash key and in others only with the call button. Furthermore, it should be noted that not every code from any vendor or any tariff is supported. Answers usually appear directly on the screen of the mobile phone, but can arrive in the form of an SMS.