INTERNATIONAL  TELECOMMUNICATION  UNION

		     ITU-T RECOMMENDATION SUMMARY


Rec. No. : T.90

Title :	Characteristics and protocols for terminals for telematic 
	services in ISDN

Study Group : VIII - Terminals for Telematics Services

Version : Revised

Date of adoption : 1992

Notes :	


Recommendation T.90 defines the functional profile for base standards 
ISO/IEC 7776, 8208 and 8885 to provide the lower layers of the 
telematic services protocol stack when operating on the ISDN.

Parameter values are recommended to ensure good throughput when 
operating via long delay connections such as satellite routes. Backward 
compatibility with the Blue Book version has been maintained.

Three methods of negotiating the lower layer parameter values have 
been included to satisfy various connection scenarios, e.g. completely 
within the ISDN or between the ISDN and other digital networks.

Recommendation T.90 supplies the network layer definition in 
Recommendation T.70 for telematic terminals but not the transport 
layer definition which is still retained as the telematic transport 
layer definition.



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