Most smartphone users only scratch the surface of what their devices can do. there are more powerful set of hidden codes we all known as USSD or MMI codes—this codes can unlock advanced features, diagnostics, and network settings.
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If you’ve ever come across the code *#21# online, you might have seen claims that it can reveal if your phone is being hacked or monitored. These claims have gone viral on social media—but how true are they?
In this guide we’ll break down what *#21# really does, and how it works, and whether you should be concerned about using it.
What Is *#21#?
*#21# is a USSD which means Unstructured Supplementary Service Data ,is being used on most smartphones to check the status of call forwarding settings on your device. If you dial this very code, your phone communicates directly with your mobile network to display information about how your calls and messages are being handled.
What Happens When You Dial *#21#?
After you are done dialing *#21#, on your smartphone, will now show a screen displaying whether call forwarding is enabled for different services, such as:
- Voice calls
- SMS (text messages)
- Data (in some cases)
Results:
- Not forwarded :Your calls are not being redirected
- Forwarded to a number: Calls are being sent to another number
This result is just an information it doesn’t change any settings on your phone.
Does *#21# Mean Your Phone Is Hacked?
No. This is one of the biggest myths online. Dialing *#21# on your phone does not:
- Detect hacking
- Reveal spyware
- Show if someone is listening to your calls
It just shows call forwarding settings, which are normal features provided by your mobile carrier.
Why Call Forwarding May Be Active
If you notice that your calls are being forwarded, don’t panic. There are many legitimate reasons:
1. Voicemail Setup
Most mobile networks will forward unanswered calls to your voicemail number.
2. Busy or Unreachable Conditions
Your calls can only be redirected when:
- When Your smartphone is switched off
- When You have no network signal
- When You are on another call
Some codes You Should Know
Here are some useful companion codes:
- ##21# : Disable all call forwarding
- *#62# : Check forwarding when your phone is unreachable
- *#67# : Check forwarding when you’re busy
- ##002# : Reset all forwarding settings completely
These codes can help you manage your call routing.
How to Turn Off Call Forwarding
If you are not sure about any forwarding settings:
- Dial ##002# to reset all forwarding
- Wait for confirmation
- Dial *#21# again to verify
This ensures your calls are no longer being redirected.
Is It Safe to Use *#21#?
Yes, *#21# is completely nice and safe.
- It does not modify your phone
- It does not expose your data
- It only displays network information
However, always be careful with other codes that may reset or erase data.
Final Thoughts
*#21# is not a secret spying code it’s just a cool way to check your call forwarding status.
Understanding what *#21# does can help you:
- Manage your call settings
- Fix network-related issues
- Avoid falling for online myths