If you’ve ever seen *#31# on a phone and wondered what on earth it does, you’re not alone. The code is connected to caller ID settings. More specifically, it lets you manage whether your phone number is shown when you make a call, although the exact behavior depends on your mobile network and phone.

What Does *#31# Actually Do?

On supported networks, *#31# is used to check or change the caller ID presentation setting for outgoing calls. In simple terms, it deals with the number that appears on someone else’s screen when you call them.

Some carriers use codes based on GSM network commands. You enter the code in the phone dialer and press the call button. Your network then handles the request.

Why Caller ID Matters]

Imagine calling someone and their phone shows “Private Number” instead of your actual number. That’s where caller ID settings come into play. If your carrier supports the command, *#31# can tell you something about how your caller ID is configured.

The exact response isn’t universal. A carrier can handle these codes differently, and some newer phones prefer letting you change caller ID through the settings menu instead.

Is *#31# the Same as Hiding Your Number?

Not quite. This is where people often get mixed up.

A caller ID restriction code is generally about suppressing your number for outgoing calls. But *#31# itself is commonly associated with checking or controlling the caller ID presentation setting, rather than simply meaning “hide my number.”

And if you’re looking for a one-time way to hide your number, your carrier may provide a different prefix for that purpose. The code varies by country and network.

• Caller ID control, which sounds technical but really means deciding what number gets displayed.

• Network-dependent behavior. Your phone can accept the code even when your carrier doesn’t support the requested service.

• A useful privacy setting, though I’d rather use the phone’s normal caller ID menu when it’s available because the result is easier to understand.

A Quick Example

Raj was trying to figure out why his number sometimes appeared as private when he called people. He spent ten minutes reopening the same five tabs every morning to check carrier instructions before finally trying the caller ID settings on his phone.

The setting explained more than the code did. That happens.

What Happens After You Enter It?

You’ll usually enter *#31# into your dialer and tap the call button. If your network recognizes the command, you may see a message showing the current caller ID status or confirming a change.

But if nothing happens, don’t assume your phone is broken. Your carrier may not support the code, or your phone may use a different method for managing caller ID.

Should You Use *#31#?

If you’re curious about your caller ID status, it’s worth trying on a network that supports GSM service codes. Just don’t treat it as a universal secret phone trick.