ETSI TS 128 062 Digital cellular telecommunications system (Phase 2+) (GSM); Universal Mobile Telecommunications System (UMTS); Inband Tandem Free Operation (TFO) of Speech Codecs; Service Description; Stage 3 (3GPP TS 28.062 version 4.1.1 Release 4)

standard by European Telecommunications Standards Institute, 08/01/2001