A ‘secret menu’ hidden inside Apple’s iPhone can only be accessed by entering codes using the digital keyboard.
The menu reveals whether your calls are being forwarded, how strong the signal strength really is, and a number to protect your smartphone, and more.
To access these features, you enter a series of numbers and symbols into your phone’s dialer as if you were about to call a number.
In most cases, to activate it, you’ll need to press ‘call’, which opens a menu page).
A ‘secret menu’ hidden inside Apple’s iPhone can only be accessed by entering codes using the digital keyboard
To access these features, you enter a series of numbers and symbols into your phone’s dialer as if you were about to call a number (Image: Rob Waugh)
Secret codes are based on Unstructured Supplementary Services Data (USSD), a communications protocol that allows devices to communicate with the network, and are typically used by technicians.
Invented in 1997, USSD sends information to your phone (like how much credit you have left) over the old GSM network.
Known as “quick codes”, “feature codes”, or “engineering codes”, these codes are often specific to certain networks and devices (although some are nearly universal).
Here are some cool features that you can unlock using codes on your iPhone.
Discover the intensity of your REAL signal
The bars your phone displays to indicate signal strength are often a pretty rough estimate, but a code on your iPhone allows you to enter field test mode to check.
To do so, type *3001# 12345#* in your phone’s dialer (it’s better to turn off Wi-Fi first)
From there, you’ll see a lot of (very) technical data about your phone: Under LTE RsrpRsrqSinr, you’ll be able to see information about your phone’s connection.
In Rsrp, you should be able to see your signal strength.
A level of -40 means a strong connection and -140 is a weaker one.
You can see how strong your signal really is. To do this, type *3001#12345#* into your phone’s dialer (Image: Rob Waugh)
Hide your caller ID
To hide your caller ID when you make a call (so the person you’re calling can’t see who called them), you can type a USSD code before the number you want to dial.
Just type *67 (in the US) to hide your number.
In Europe, try #31#.
This feature depends on whether your network supports it (so it may not be available on certain networks or plans).
Find your IMEI number to protect your phone
You can access your IMEI number directly from your dial pad, which will help if you lose your phone (Image: Rob Waugh)
Knowing your unique International Mobile Equipment Identity (IMEI) number can help your carrier block you if you lose your phone.
To view yours, simply type *#06#, write it down, and then if your phone is lost or stolen, contact your carrier.
See if your calls are being forwarded
You can check if your calls are being forwarded (usually this would be to your voicemail, but this can also check if someone has set your calls to forward somewhere else).
To view your forwarding settings, type the USSD *#67#.
Enable call barring
You can simply enable call barring (which blocks incoming calls) by entering a USSD.
To check if you have call barring enabled, type *#33#.
To enable it, you will need your SIM PIN (if you don’t know it, contact your network provider)
To enable call barring, enter *33*SIM PIN#.
To disable it, enter #33*pin#.
Forward your calls to another phone
To forward your calls to another phone, simply enter a USSD code.
To do this, type *21PHONENUMBER# and the phone will start forwarding your calls (type the full phone number where it says PHONENUMBER.
This varies by network, so if you get an error message, use *72 instead of *21.
To turn it off again, type *21#.