Polycom RealPresence RMX 1500 Administrator's Manual page 247

Supported Audio Algorithm vs Bitrate
Audio Algorithm
G.722.1 16K
G.722 48K
G.722 56K
G.722 64K
G.711 56K
G.711 64K
G.728 16K
G.722.1C 32K
G.722.1C 24K
Siren14 32K
Siren14 24K
G.722.1 32K
G.722.1 24K
G.722 48K
G.722 56K
G.722 64K
G.711 56K
G.711 64K
G.728 16K
G.722.1 16K
G.722.1C 24K
Siren14 24K
G.722 48K
G.722 56K
G.722 64K
G.711 56K
G.711 64K
G.728 16K
G.728 16K
Polycom®, Inc.
Additional Conferencing Information
Minimum Bitrate (kbps)
256
128
96
64
216