INTERNATIONAL  TELECOMMUNICATION  UNION

		     ITU-T RECOMMENDATION SUMMARY


Rec. No. : G.706

Title : Frame alignment and cyclic redundancy check (CRC) procedures 
	relating to basic frame structures defined in 
	Recommendation G.704

Study Group : XV - Transmission Systems and Equipment

Version : Revised

Date of adoption : 1991

Notes :	


Recommendation G.706 relates to equipment which receives signals with 
basic frame structures as defined in Recommendation G.704. It defines 
the frame alignment, the cyclic redundancy check (CRC) multiframe 
alignment and CRC bit error monitoring procedures to be used by such 
equipment. It contains background information about the use of the 
CRC procedures and their limitations.

It gives details of a modified CRC-4 multiframe alignment algorithm 
which allows automatic interworking between equipment with and 
without a CRC-4 capability. It gives also details regarding the 
updating of CRC-4 information when an intermediate equipment 
(i.e. between true path terminating equipments) has a write-access to 
a message-based data-link facility.



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