Smartphones contain many features that most users never discover. The iPhone, designed by Apple Inc., includes several hidden dial codes that allow users to access diagnostic tools, network information, and call settings directly from the phone dialer.
These codes, often called USSD codes or service codes, can perform useful tasks such as:
- Displaying the IMEI number
- Opening Field Test Mode for signal strength
- Checking call forwarding status
- Managing call waiting
- Viewing voicemail settings
- Accessing carrier service numbers
Many of these codes work across most mobile networks and iPhone models, although availability may vary depending on your telecom provider and region.
Understanding these codes can help you troubleshoot network issues, verify phone identity, or manage call features quickly without navigating complex settings menus.
What Are iPhone Secret Codes?
iPhone secret codes are special numeric commands typed into the phone dialer that activate built-in system functions.
These codes are part of the GSM (Global System for Mobile Communications) standard, which means many Android phones and feature phones support similar commands.
Instead of navigating multiple menus, users can simply dial a code and press the call button to trigger the function.
Example
Dial:
*#06#
Your phone instantly displays the IMEI number.
Think of secret codes as shortcuts into deeper system functions.
How iPhone Secret Codes Work
Secret codes communicate with your phone’s baseband software, which manages communication with mobile networks.
When you dial a code, the phone interprets it as a system command instead of a normal phone number.
The system then triggers:
- A network query
- A system diagnostic tool
- A configuration command
This is why the result appears immediately without placing a call.
Complete List of iPhone Secret Codes
Below is a clear table explaining the most useful iPhone dial codes.
| Code | Function |
|---|---|
| *#06# | Show IMEI number |
| 3001#12345# | Field Test Mode |
| *#21# | Call forwarding status |
| *#62# | Check voicemail forwarding |
| *#67# | Check forwarding when busy |
| *#33# | Call barring status |
| #50057672# | SMS service center number |
| *#31# | Hide caller ID |
| *#43# | Call waiting status |
| *#76# | Connected line presentation |
| *#61# | Check call forwarding delay |
| *3370# | Enhanced voice quality |
| #500586# | Voicemail number |
| #50057672# | Service center number |
| *#225# | Postpaid balance check |
| *777# | Prepaid balance check |
| *43# | Activate call waiting |
| #43# | Deactivate call waiting |
Now let’s explore what each of these codes actually does.
*#06# – Show IMEI Number
The IMEI (International Mobile Equipment Identity) is a unique 15-digit identifier assigned to every mobile phone.
Why IMEI Is Important
It helps:
- Identify your device globally
- Track stolen phones
- Verify device authenticity
Example Use
If your phone is lost or stolen, the IMEI can be used by your carrier to block the device from mobile networks.
3001#12345# – Field Test Mode
Field Test Mode opens a hidden engineering menu showing detailed network statistics.
You can view:
- Signal strength in dBm
- Network band information
- LTE connection details
- Cell tower data
Why This Is Useful
Signal bars are often misleading. Field Test Mode shows precise signal strength numbers, helping diagnose connectivity problems.
*#21# – Check Call Forwarding Status
This code reveals whether all incoming calls are being forwarded to another number.
Useful For
- Checking if forwarding was activated accidentally
- Troubleshooting missed calls
- Verifying telecom service settings
*#62# – Check Voicemail Forwarding
If your phone is unreachable, calls may be redirected to voicemail.
Dialing this code shows:
- The voicemail number
- Forwarding configuration
*#67# – Check Forwarding When Busy
When you are already on another call, your phone may redirect incoming calls.
This code tells you:
- Where busy calls are forwarded
- Whether forwarding is active
*#33# – Check Call Barring Status
Call barring prevents certain calls from being made or received.
For example:
- Blocking international calls
- Blocking outgoing calls
This code displays whether call barring restrictions are active.
#50057672# – SMS Service Center Number
Every carrier has a Short Message Service Center (SMSC) responsible for sending text messages.
This code displays the service center number used by your SIM card.
Why It Matters
If SMS messages fail to send, the SMSC number may be misconfigured.
*#31# – Hide Caller ID
This code allows you to hide your phone number when calling someone.
Instead of displaying your number, the recipient sees:
- Private number
- Unknown caller
*#43# – Call Waiting Status
Call waiting allows users to receive another call while already on a call.
This code checks whether call waiting is enabled or disabled.
*#76# – Connected Line Presentation
This feature controls whether the recipient’s phone number appears after the call connects.
It’s mostly used in telecom diagnostics.
*#61# – Check Call Forwarding Delay
This command shows how long the phone waits before forwarding an unanswered call to voicemail.
Typical delay values include:
- 15 seconds
- 20 seconds
- 25 seconds
- 30 seconds
*3370# – Enhanced Voice Quality Mode
This code activates Enhanced Full Rate (EFR) voice coding.
Benefits
- Clearer call quality
- Better voice clarity
Drawback
It may slightly reduce battery life.
#500586# – Voicemail Number
This code displays the voicemail access number stored on your SIM card.
#50057672# – Service Center Number
Displays the network SMS service center address.
This information is useful when diagnosing text message delivery problems.
*#225# – Check Postpaid Balance
Some carriers allow postpaid users to dial this code to check:
- Bill summary
- Data usage
- Remaining limits
Availability depends on telecom providers.
*777# – Check Prepaid Balance
Prepaid users can dial this code to check:
- Remaining talk time
- Data balance
- Validity
Note that telecom providers sometimes replace this with custom USSD codes.
*43# – Activate Call Waiting
Typing this code enables call waiting on your phone.
Once activated, incoming calls will notify you even when you are already on a call.
#43# – Deactivate Call Waiting
This code disables call waiting so that incoming calls go directly to voicemail or receive a busy signal.
Did You Know?
1. Every iPhone Has an IMEI
Even if your phone has no SIM card, it still has an IMEI number stored in hardware.
2. Field Test Mode Was Originally Designed for Engineers
This mode was created for network engineers to measure signal quality, but anyone can access it using a simple dial code.
3. Secret Codes Work Without Internet
These commands interact with the mobile network and device firmware, so they work even without Wi-Fi or mobile data.
Are iPhone Secret Codes Safe?
Yes—most codes are read-only commands that display information rather than modify settings.
However, you should:
- Only use trusted codes
- Avoid unknown internet commands
- Never share your IMEI publicly
Common Reasons People Use iPhone Secret Codes
Users often dial these codes for several practical reasons:
Network Troubleshooting
Checking signal strength or call settings.
Device Verification
Confirming IMEI numbers before buying used phones.
Carrier Diagnostics
Understanding forwarding or voicemail settings.
Privacy Control
Hiding caller ID when necessary.
FAQs About iPhone Secret Codes
What is the most useful iPhone secret code?
The most widely used code is *#06#, which instantly displays the phone’s IMEI number.
Do secret codes work on all iPhones?
Most codes work on all iPhones, but some depend on the mobile carrier and network technology.
Can secret codes damage my iPhone?
No. Most codes only display information or toggle network settings, making them safe to use.
Why doesn’t Field Test Mode work on my phone?
Some carriers restrict access to advanced diagnostic tools, so the code may behave differently depending on the network.
Are these codes exclusive to iPhone?
No. Many secret codes originate from the GSM telecom standard, meaning Android phones also support similar commands.
