FRITZ!Box 7330 Service - Knowledge Base

FRITZ!Box 7330 Service

Suppressing your telephone number

You can suppress your telephone number when making calls so that it is not transmitted to the party you are calling. That way the party you are calling does not see your number in the display of their telephone. This function is called "CLIR" (Calling Line Identification Restriction). You can either suppress your caller ID for a single call or permanently suppress it for all calls.


  • Your telephony provider must have enabled Calling Line Identification Restriction (CLIR) on a call-by-call basis for your telephone line.

Note:All instructions on configuration and settings given in this guide refer to the latest FRITZ!OS for the FRITZ!Box.

1 Suppressing the number on a case-by-case basis (for a single call)

You can suppress your caller ID for a single call. Your caller ID will be transmitted again when you make subsequent calls:

Configuring a telephone to use the keypad function

Keypad sequences are strings of characters and numbers that you can use to enable or disable functions. You can use keypad sequences immediately with telephones, such as FRITZ!Fon C5, that are registered with the base station of your FRITZ!Box. If you are using a cordless telephone that is not registered with the FRITZ!Box's base station, you must first set up the keypad function:

  1. Configure the telephone so you can send keypad sequences (sequences of symbols and numbers, such as *121#) and enter special characters such as * and # with it. On many telephones, you can configure this function in the menu "Operation at a PBX > Dialing options > Dial * and #".

Blocking your telephone number for the next call

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

    To suppress your number when calling the telephone number 0301234, enter *31#0301234.

2 Permanently suppressing your caller ID (for all calls)

You can also permanently suppress your caller ID for all calls. To do so, you must enable CLIR (Calling Line Identification Restriction) in the FRITZ!Box or your telephone. The procedure depends on the type of telephone you are using:

Note:If you have enabled permanent suppression of the caller ID, you can still transmit your caller ID for one call. To do so, simply enter the prefix #31# before the actual number, for example #31#0301234. Your caller ID will now be transmitted only for this call and blocked for the following calls.

Enabling CLIR for analog and cordless telephones

  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.

Enabling CLIR for IP telephones

  1. Enable the CLIR function directly on the IP telephone. Refer to the device's manufacturer for information on how to set it up, for example consult the manual.

    Note:You can enable CLIR in FRITZ!App Fon by tapping "More > Settings > Tel. No. Suppressed".