prENV 50XXX

Signalling protocols on PTNX extension lines - S reference point, basic and primary rate access - 1) a: layer 1 sign. prot. BA at the S ref. pt., Subset for data proc. terminals; b: layer 1 sign. prot. BA at the S ref. pt., general specification; 2) layer 1 sign. prot. PMA at the S ref. pt