Indigital telecommunications networks, the caller's telephone number is transmitted to the called party. If a subscriber does not want his or her telephonenumberto be transmitted to the called party, there is the option of 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. In the case of 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.