Code: *#21# Meaning and Addressing The Code 21 Hoax

Jonathan Kao

Code 21 Meaning

Many smartphone users may have seen the *#21# access code on their phones, but they may not be aware of its purpose or function. This code, known as USSD (Unstructured Supplementary Service Data), is widely used across various service providers and can be used on both iPhones and Android devices. When this code is entered into the phone and dialed you’ll get information about the call forwarding settings on the phone. It will tell you if forwarding is active and to which number the calls might be forwarded to. That’s pretty much it.

Despite some misconceptions, this code does not inform users if their communication has been interfered with or if their device is under surveillance. Instead, it serves a simpler, less dramatic purpose: allowing users to quickly check their call forwarding status without having to navigate through the settings app. It is part of a suite of feature access codes that enable users to manage various phone settings directly from the dialer.

Addressing The *#21# Hoax (Code 21 Hoax)

There have been rumors circulating online that dialing *#21# checks for phone hacking. This is entirely untrue. The *#21# code only displays your call forwarding status and does not provide any information about hacking or phone security.

So Can Dialing Code 21 Tell Me If My Phone Was Tapped By The FBI or Someone Else?

No. It can’t. That’s the hoax that goes viral every few years. The point of the hoax is to scare you into thinking that the somewhat long and confusing response you get back by dialing the number is something sinister, when in fact it isn’t. If you’re concerned about your phone’s security, it’s recommended to:

Download apps only from trusted sources.
Be cautious about clicking on links in text messages or emails.
Use strong passwords and enable two-factor authentication.
Consider installing a reputable mobile security app.
By following these tips, you can help keep your phone safe and secure

Here’s the type of response you’ll get on iPhone:

Decoding the *#21# Code: Understanding Call Forwarding

Dialing *#21# on your phone might seem cryptic, but it serves a simple purpose – checking your call forwarding status. Here’s how this code works and what it indicates.

What is Call Forwarding?

Call forwarding allows you to redirect incoming calls to a different phone number. This feature is useful in various scenarios:

  • If you’re unavailable: You can forward calls to voicemail or another phone number when you’re unable to answer.
  • Traveling: Direct calls to a local number while you’re in a different location.
  • Work-life separation: Forward business calls to your work phone during off-hours.

How to Use the *#21# Code

  1. Dial *#21#: Open the phone app on your device and enter *#21# as if you’re making a call.
  2. Press Call: Tap the call button.
  3. See Results: Your phone will display the current call forwarding status for different scenarios.

Interpreting the Results

Here’s a table outlining the common responses when you dial *#21# and what they mean:

Voice Call Forwarding: [Phone Number]Outgoing calls are being forwarded to the specified number
Data Call Forwarding: [Phone Number]Data calls are being forwarded
Fax Call Forwarding: [Phone Number]Fax calls are being forwarded
SMS Call Forwarding: [Phone Number]Text messages are being forwarded
Settings Not InterrogatedUnable to retrieve current settings, often means call forwarding is not active


  • The *#21# code is a standard feature for most GSM carriers like AT&T and T-Mobile.
  • You can usually also find and modify call forwarding settings directly within your phone’s settings menu.

Key Takeaways

  • The code *#21# informs users about call forwarding settings.
  • This USSD code works on various smartphones and service providers.
  • It is not a tool to detect phone surveillance or tapping.

Understanding *#21# and Call Forwarding

To grasp the concept of the *#21# code, it is essential to understand its role in call forwarding. This code checks whether your phone redirects incoming calls, messages, or data elsewhere without your input.

The Functionality of *#21#

The *#21# code is an interrogation code that allows one to check the status of call forwarding on a device. If a customer enters this code into their phone’s dialer and executes the command, their device will display whether various types of calls, like voice calls or data calls, as well as SMS and voice messages, are being forwarded. This is crucial information for users, as it informs them if their incoming communications are possibly being routed to another number.

Interactions with Carriers and Devices

This USSD code (Unstructured Supplementary Service Data) generally works across various carriers including Verizon, AT&T, and T-Mobile. However, the effectiveness of the code can vary depending on the carrier and whether the device is an iPhone, Samsung, Android or another smartphone. Service providers offer these self-service short codes to empower customers, enabling them to access phone settings typically hidden in menus that most users don’t explore.

Security Implications

Using *#21#, individuals can quickly assess if their line has been compromised, potentially indicating spyware or unauthorized call forwarding often associated with wiretapping. The general public may encounter social media posts or hoaxes suggesting the code can unveil if a phone is being tapped by entities like the CIA or law enforcement. While it’s imperative for one’s technological security to verify that their connection has not been hacked, it is just as important to discern fact from fiction. Notably, *#21# merely shows the call forwarding status and doesn’t indicate phone tapping.