DETECTING LOCATION OF TIME SLOT WHERE DATA BEGINS USING POINTER IN JUSTIFICATION OR STUFFING SYNCHRONOUS TDM

摘要

In a synchronous TDM communications system whereinthe data is transmitted after being subject to zero,negative or positive justification, a location of a timeslot where data having a predetermined length begins, isspecified by detecting a pointer. The pointer, which isincluded in a demultiplexed channel information, isextracted from the demultiplexed channel information.Further, a pointer value indicative of the predeterminedlength is detected. Still further, a justificationstatus is also detected using the pointer extracted. Onthe other hand, a timing signal is received whichcorresponds to the zero justification. A pointer offsetis produced using the timing signal, while anotherpointer offsets are generated by advancing and retardingthe pointer offset by one time slot. Subsequently, oneof the three offsets is selected depending on thejustification status. A comparator compares the pointeroffset selected and the pointer value and outputs asignal indicative of the first time slot of the data inthe event that the comparison coincidence has beendetected.