The Short Version
If you want to make a call without your number showing up on the other end, there's a short code you can type before the number: `#31#` in most of the world, `*67` in the US and Canada. Type it, dial the number right after it, and your caller ID is hidden for that one call.
That's the manual method, and it works. It's also the exact thing Pcaller automates, so you stop typing it altogether. Here's how the code works under the hood, and why most people who use it regularly eventually switch to letting an app handle it.
---
How the Code Actually Works
Your phone number is transmitted as part of every call you make - it's part of the signal sent the moment you tap call. The prefix code instructs your carrier's network, before the call connects, to strip your number out of the data sent to the recipient's phone.
You're essentially flagging to your carrier: don't forward my number on this one. The call goes through exactly as normal - same connection, same quality - but the recipient's phone receives no number to display. Instead it shows "No Caller ID," "Private," or "Unknown."
`*67` and `#31#` do the identical thing. The difference is just which network signaling standard your carrier uses - US/Canadian networks respond to `*67`, while GSM networks (most of the rest of the world) respond to `#31#`.
---
What Pcaller Does Instead
Pcaller takes the exact same underlying mechanism - the prefix code - and removes the part where you have to remember and type it.
You configure your prefix once, matching your country and carrier. From that point on, every call you place through Pcaller has that code applied automatically - whether you tap a contact's name or dial a number manually on the keypad. Either way, you never type the code yourself.
What changes in practice:
- Calling from contacts or the keypad works the same way. Tap a name or dial manually - the prefix is added behind the scenes either way.
- You can switch modes instantly. One tap moves you between private and normal calling, instead of editing the dial string by hand each time.
- The prefix is adjustable in one place. If you travel or change carriers and need a different code, you update it once in the app instead of remembering a new code to type manually.
- Your call history tells you what happened. You can see which calls actually went out as private, instead of trusting that you typed the code correctly.
The call itself is identical either way - same carrier line, same call quality, same "No Caller ID" result on the other end. Pcaller doesn't change what the call does. It changes how much effort it takes you to make it happen.
---
When the Code Doesn't Work (Either Way)
A few limitations apply whether you type the code manually or let Pcaller apply it automatically, because they're determined by the network, not by how the prefix gets dialed:
- Some recipients block hidden calls entirely. If their phone or business system rejects calls with no caller ID, the call won't connect - this is on their end, not something either method can override.
- Some carriers don't honor the code. If your specific carrier doesn't support prefix-based hiding, neither typing it manually nor using an app will change that - the network simply ignores the instruction.
- Emergency services always see your real number. This is a legal requirement everywhere, and no prefix or app changes it.
- Toll-free numbers can sometimes see through it. Businesses using these numbers often have visibility regardless of blocking.
---
Which Approach Makes Sense for You
If you hide your number once in a blue moon, typing `#31#` or `*67` manually before a number is fine - it's a few extra keystrokes, not a big deal.
If you find yourself doing this regularly - work calls, classified ads, situations where privacy matters more often than not - typing the same code over and over, every single time you dial, becomes the kind of small friction that's worth removing.
That's the entire reason Pcaller exists: same result, same network mechanism, none of the repetitive manual work.