INTERNATIONAL  TELECOMMUNICATION  UNION

		     ITU-T RECOMMENDATION SUMMARY


Rec. No. : Q.81.3

Title :	Stage 2 description for number identification supplementary 
	services

Study Group : XI - Switching and Signalling

Version : Revised

Date of adoption : 1991

Notes :	


    CALLING LINE IDENTIFICATION PRESENTATION (CLIP) AND CALLING LINE 
		    IDENTIFICATION RESTRICTION (CLIR)

Recommendation Q.81.3 defines the stage 2 of the integrated services 
digital network (ISDN) as provided by the telecommunications operators 
for the Calling Line Identification Presentation (CLIP) and Calling 
Line Identification Restriction (CLIR) supplementary services. Stage 2 
identifies the functional capabilities and the information flows 
needed to support the service description. The stage 2 description 
also identifies user operations not directly associated with a call 
(see Recommendation I.130).

Recommendation Q.81.3 is defined according to the methodology 
specified in Recommendation Q.65.

Recommendation Q.81.3 does not formally describe the relationship 
between these supplementary services and the basic call but, where 
possible, this information is included for guidance.

In addition, Recommendation Q.81.3 does not specify the requirements 
where the service is provided to the user via a private ISDN. 
Recommendation Q.81.3 does not specify the requirements for the 
allocation of defined functional entities within a private ISDN; it 
does however define which functional entities may be allocated to a 
private ISDN.

Recommendation Q.81.3 does not specify the additional requirements 
where the service is provided to the user via a telecommunications 
network that is not an ISDN.

The CLIP supplementary service provides the called party with the 
possibility to receive identification of the calling party.

The CLIR supplementary service enables the calling party to prevent 
presentation of its ISDN number to the called party.

The CLIP and CLIR supplementary services are applicable to all 
telecommunication services.

Recommendation Q.81.3 is applicable to the stage 3 Recommendations for 
the ISDN CLIP and CLIR supplementary services, as defined in 
Recommendation I.130.



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