Polycom RealPresence 1500 Administrator's Manual page 255

Siren22Stereo, G.719Stereo and SirenLPR vs Bitrate
Audio Algorithm
Siren22Stereo_96k
SirenLPRStereo_96k
G.719Stero_96k
Siren14Stero_96k
SirenLPRStereo_64k
G.719Stereo_64k
Siren22Stereo_64k
Siren14Stereo_64k
Audio algorithms supported for ISDN (1500/2000/4000)
Supported Audio Algorithm vs Bitrate
Audio Algorithm
G.722.1C 48K
G.722.1C 32K
G.722.1C 24K
Siren14 48K
Siren14 32K
Siren14 24K
G.722.1 32K
G.722.1 24K
G.722.1 16K
G.722 48K
G.722 56K
G.722 64K
G.711 56K
G.711 64K
G.728 16K
Polycom®, Inc.
Additional Conferencing Information
Minimum Bitrate (kbps)
512
384
Minimum Bitrate (kbps)
256
256
225