FRITZ!App Fon Service - Knowledge Base

FRITZ!App Fon Service

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 block" or "CLIR" (Calling Line Identification Restriction). You can either block your caller ID for just a specific call or on all of your calls.


  • Your telephony provider must have enabled the function caller ID block on a call-by-call basis for your telephone line.

1 Blocking caller ID for a specific call

You can block your caller ID for just a single call. Afterwards, your caller ID will be displayed again when you make calls:

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

    To block your caller ID when calling the telephone number 0301234, enter *31#0301234.

2 Permanently blocking your caller ID (for all calls)

  1. Start FRITZ!App Fon.
  2. Tap "More" and then "Settings".
  3. Enable the option "Tel. No. Suppressed".