APPENDIX A: ITU Audio Standards

The standards are grouped alphabetically and can be found at http://www.itu.int/rec/recommendation.asp?type=series&lang=e&parent=T-REC or at http://www.ituaj.or.jp/book/itut-rec.html

G.711 - Pulse code modulation (PCM) of voice frequencies - This is what is used on our telephone system today. It is uncompressed low bandwidth audio around 3 kHz.

G.722 - 7 kHz audio-coding within 64 kbps – Provides better audio transmission at higher frequencies allowing for more natural sounding audio.

G.722.1 - Compresses 50Hz - 7kHz audio signals into one of two bit rates, 24 kbit/s or 32 kbit/s. This standard also incorporates hands-free operation in systems with low frame loss.

G.728 - Coding of speech at 16 kbps using low-delay code excited linear prediction

G.723.1 - Dual rate speech coder for multimedia communications transmitting at 5.3 and 6.3 kbps