What is *# 21 on iPhone?

*What is # 21 on iPhone?**

The *#21# code is a USSD code, also known as a Dual Tone Multi-Frequency code, used to access special features on iPhone and other mobile phones. This code is not specific to a particular operator or region, and its functions remain the same across various carriers.

*What Does # 21 Do on an iPhone?**

Reset Network Settings: #21# is primarily used to reset the iPhone’s network settings, also known as EFR (Enhanced Frequency Division Duplex). By entering #21#, the user resets the iPhone’s automatic configuration from the cellular network. This feature comes in handy when faced with cellular connectivity issues, including network-related errors or when encountering issues after switching SIM cards.

View Complete Answer On Apple

Here’s the answer taken from Apple:

"*#21# is a troubleshooting code used by your carrier’s network settings to force the device to re-regenerate and re-store all of the current network-related data…"

*When To Use #21#**

1. Troubleshooting: Use this code to identify and resolve network connectivity issues.
2. SIM Issues: Try *#21# if you’ve just switched to a new SIM card and are having trouble connecting.
3. Reset Network: Apply this code if you’ve noticed incorrect or old network settings on your device.
4. Reset to Defaults: If the cellular network settings are interfering with device functionality, use this code to restore default settings.

iPhone and USSD Codes: Benefits and Disadvantages

Benefits

1. Troubleshooting: Convenient and quick fixes for cellular connectivity issues.
2. SIM Reset: Effortlessly re-establish connectivity after switching SIM cards.
3. Network Restoration: Forces your device to re-generate correct network settings.
4. Trouble-Shooting Tool: *#21# code provides an additional way to troubleshoot device connectivity issues.

Disadvantages

1. Complexity: Code entry can be lengthy and frustrating.
2. Frequent Restarting: *#21# often requires restarting your iPhone, disrupting ongoing activities.

Alternative Method:

Instead of entering the code manually, you can take a quick and easy way: navigate to the Settings app -> General -> Reset -> Reset Network Settings, followed by confirming "Reset" or "Reset Network." This reset process achieves similar effects, resetting iPhone’s network settings from within the device.

Conclusion

The #21# USSD code, specifically designed to resolve iPhone cellular connectivity issues, offers a practical troubleshooting and resetting solution for a wide range of network-related problems. To harness this feature, simply type the code #21# on your iPhone keypad and wait for the results. Note that if you encounter more persistent network issues, it may be helpful to restart your device or seek the help of a technician.

References

• Apple, Inc. (2021, August 27). "*#21# is a troubleshooting code…" retrieved from here

This new article aims to provide readers with in-depth information about what *#21# on iPhone stands for and the various uses for this code, while also comparing benefits and limitations.