prENV 50XXX

Signalling protocols on PTNX extension lines S reference point, basic and primary rate access - 3) layer 2 sign. prot. at the S reference point, pt/mpt; 4) layer 2 sign. prot. at the S reference point, pt/pt; 5) layer 3 sign. prot. at the S reference point, basic call, circuit switched; 6) suppl. services sign. prot. at the S reference point