ETSI - TS 122 081
Digital cellular telecommunications system (Phase 2+) (GSM); Universal Mobile Telecommunications System (UMTS); Line Identification supplementary services; Stage 1
|Publication Date:||1 April 2022|
The present document describes the Supplementary Services belonging to the group Line Identification Supplementary Services.
The general aspects, including definitions and recommended provision, of the description of the Supplementary Services are given in 3GPP TS 22.004.
The group of Line Identification Supplementary Services is divided into the following four Supplementary Services:
CLIP - Calling line identification presentation (clause 1);
CLIR - Calling line identification restriction (clause 2);
COLP - Connected line identification presentation (clause 3);
COLR - Connected line identification restriction (clause 4).
Definition of line identity: The line identity is made up of a number of information units:
- the subscriber's national ISDN/MSISDN number (MSISDN number is the number stored in the VLR);
- the country code;
- optionally, subaddress information. The PLMN cannot be responsible for the content of this subaddress. (For definition of the subaddress see ITU-T Recommendation E.164  subclause 11.2).
In a full ISDN environment, the line identity shall include all the address information necessary to unambiguously identify a subscriber.
The calling line identity is the line identity of the calling party.
The connected line identity is the line identity of the connected party.
If for the line identity of the calling party or the connected party additional line identification is received (additional calling party/connected party number) in a PLMN this additional line identification shall be used for the presentation purpose of the line identification presentation services.
Definition of Presentation and Screening Indicators: In addition to or instead of the line identity, the network may give a Presentation Indicator (PI) and/or a Screening Indicator (SI) to the served subscriber. The following information may be given:
- Presentation Indicator showing:
a) presentation allowed, or
b) presentation restricted, or
c) number not available due to interworking;
If Presentation Indicator is set to "Presentation Restricted", then the MS can get additional information on the Cause of no CLI, if provided by the network.
The Cause of no CLI value may be one of the following :
- reject by user
- interaction with other services
- coin line / pay phone
- Screening Indicator showing:
a) user provided, verified and passed, or
b) user provided, not screened, or
c) network provided.
If the line identity is that of a PLMN subscriber, then:
the national number and the country code shall always be provided by the network;
the subaddress shall only be included if it is provided by the user (or user equipment);
the screening indicator shall indicate "network provided".