To the knowledge base

Blocking your telephone number from being displayed

You can block your telephone number from being displayed when you make a call. That way, the person you are calling does not see your number in the display of their telephone. This function is called "caller ID blocking" or "CLIR" (Calling Line Identification Restriction). You can either block your telephone number (caller ID) for just a specific call or for all of the calls you make.


  • The feature "caller ID blocking (CLIR) for individual calls" must have been enabled by your telephony provider.

1 Blocking caller ID for a specific call

You can block your caller ID for just one call. After that call, your caller ID will be displayed every time you make a call:

  1. When making a telephone call, enter *31# and then the number you want to call. Your caller ID will then be blocked for that call.

    Enter *31#0301234 to block your caller ID when calling the telephone number 0301234.

2 Permanently blocking your caller ID (for all calls)

  1. Start FRITZ!App Fon.
  2. Tap the the three-dot menu on the top right (Android) or "More" (iOS) and then tap "Settings".
  3. Enable the option "Tel. No. Suppressed".