Secret codes, technically known as USSD (Unstructured Supplementary Service Data) codes or MMI (Man-Machine Interface) codes, are protocols used by smartphones to communicate with the mobile network operator or the phone’s internal firmware.
On the Galaxy A55 5G, you can tap Menu → Back then Key Input and enter Q to unlock advanced band selection menus (requires caution). How to Use Secret Codes on SAMSUNG Galaxy A55 5G
Band Selection – allows you to force the phone to use specific 4G/5G bands. Use case: If your carrier has congested bands, you can lock onto a cleaner frequency. Warning: Changing this without knowledge may cause signal loss. Use case: If your carrier has congested bands,
Displays technical network connection and cell signal information. Troubleshooting: If Codes Aren't Working Troubleshooting: If Codes Aren't Working This is the
This is the most universal code across all mobile devices.
Note: Carrier-locked A55 models (e.g., Verizon, AT&T, Jio) may block even these working codes. Test *#06# first – if that doesn't work, none will.