INTERNATIONAL  TELECOMMUNICATION  UNION

		     ITU-T RECOMMENDATION SUMMARY


Rec. No. : Q.731.8

Title :	Stage 3 description for number identification supplementary 
	services using signalling system No. 7

Study Group : XI - Switching and Signalling

Version : New

Date of adoption : 1992

Notes :	


			SUB-ADDRESSING (SUB)

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

The stage 1 service description is given in Recommendation I.251.8 and 
the stage 2 functional capabilities and information flows are given in 
Recommendation Q.81.8. The stage 3 description of the sub-address 
supplementary service uses the ISDN user part protocol as defined in 
Recommendations Q.761 to Q.764 and Q.767.

The sub-address information is access significant information which is 
transported transparent through the network in the access transport 
parameter in the initial address message (IAM).



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