ETSI TR 101 294
ETSI TR 101 294
Digital cellular telecommunications system (Phase 2+) (GSM); Subjective tests on the interoperability of the Half Rate/Full Rate/Enhanced Full Rate (HR/FR/EFR) speech codecs, single, tandem and tandem free operation (GSM 06.85 version 7.0.0 Release 1998)
standard published 08/01/1999 by European Telecommunications Standards Institute