FRITZ!Fon M2 Service - Knowledge Base

FRITZ!Fon M2 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.


  • The FRITZ!Fon must be registered with a FRITZ!Box.
  • 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. Press the "Menu" key on the telephone.
  2. Scroll to "Settings" and press "OK".
  3. "Telephony" > "OK" > "Anonymous call" > "OK"
  4. Enable the option "Next call".
  5. Press the "end call" key.

2 Permanently blocking your caller ID (for all calls)

  1. Click "Telephony" in the FRITZ!Box user interface.
  2. Click "Telephony Devices" in the "Telephony" menu.
  3. Click the (Edit) button for the respective telephone.
  4. Click on the "Telephony Device Features" tab.
  5. Enable the option "Calling line identification restriction (CLIR)".
  6. Click "OK" to save the settings.