In digital telecommunications networks, the caller's telephone number is transmitted to the called party. If a subscriber does not want his call number to be transmitted to the called party, there is the possibility of call number suppression, the Calling Line Identification Restriction (CLIR).
This prevents the called party from identifying the calling party before the call is recorded. There are the options of permanent or temporary suppression. With case-by-case suppression, a default setting is made in the exchange according to the options "Suppress" or "Do not suppress". Call number suppression always has priority over its transmission.