Summary

1               This Recommendation defines the operation of the Digital Subscriber Signalling System No. 2 (DSS 2) for the support of the following number identification supplementary services:

Clause 1           –     Direct-Dialling-In (DDI)

Clause 2           –     Multiple Subscriber Number (MSN)

Clause 3           –     Calling Line Identification Presentation (CLIP)

Clause 4           –     Calling Line Identification Restriction (CLIR)

Clause 5           –     Connected Line Identification Presentation (COLP)

Clause 6           –     Connected Line Identification Restriction (COLR)

Clause 8           –     Sub-addressing (SUB)

The Recommendation defines the operation for the support of the services at the T_B or at the coincident S_B and T_B reference point of the user to network interface of the Broadband Integrated Services Digital Network (B-ISDN).

2           A brief description of the services is the following:

This DDI supplementary enables a user to call directly to another user on a B-ISDN private branch exchange or other private systems, without attendant intervention, based exclusively on the use of the ISDN number.

The MSN supplementary service provides the possibility for assigning multiple ISDN numbers to a single public or private access.

Calling Line Identification Presentation (CLIP) is a supplementary service offered to the called party which provides the calling party’s ISDN number, possibly with sub-address information, to the called party.

Calling Line Identification Restriction (CLIR) is a supplementary service offered to the calling party to restrict presentation of the calling party’s ISDN number and sub-address to the called party.

Connected Line Identification Presentation (COLP) is a supplementary service offered to the calling party which provides the connected party’s ISDN number, possibly with sub-address information, to the calling party.

Connected Line Identification Restriction (COLR) is a supplementary service offered to the called party to restrict presentation of the connected party’s ISDN number and sub-address to the calling party.

The sub-addressing supplementary service allows the called (served) user to expand his addressing capacity beyond the one given by the ISDN number.