INTERNATIONAL  TELECOMMUNICATION  UNION

		     ITU-T RECOMMENDATION SUMMARY


Rec. No. : Q.84.2

Title :	Stage 2 Description for multiparty supplementary services

Study Group : XI - Switching and Signalling

Version : New

Date of adoption : 1992

Notes :	


		     THREE-PARTY SERVICE (3PTY)

Recommendation Q.84.2 defines the stage 2 of the Three-Party 
supplementary service. Stage 2 identifies the functional capabilities 
and the information flows needed to support the service as described 
in stage 1. The stage 2 description also identifies user operations 
not directly associated with a call (see Recommendation I.130).

Recommendation Q.84.2 is specified according to the methodology 
specified in Recommendation Q.65.

In addition, Recommendation Q.84.2 does not specify the requirements 
where the service is provided to the user via a private ISDN. This 
Recommendation 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.84.2 does not specify the additional requirements 
where the service is provided to the user via a telecommunications 
network that is not an ISDN.

The Three-Party supplementary service enables a user who is involved 
in, at least, two calls (on active call and at least on call on hold) 
to join the two calls together into a 3-way conversation, i.e. a 
simultaneous communication between the served user and two other 
parties.

This supplementary service is not applicable to non-voice services.

Recommendation Q.84.2 is applicable to the stage 3 standards for the 
integrated services digital network.



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