ETSI TS 123 091
ETSI TS 123 091
Digital cellular telecommunications system (Phase 2+) (GSM); Universal Mobile Telecommunications System (UMTS); Explicit Call Transfer (ECT) supplementary service - Stage 2 (3GPP TS 23.091 version 4.0.0 Release 4)
standard published 03/01/2001 by European Telecommunications Standards Institute
