Yamaha CS-700 Operation Manual page 30

Media Settings
Media Settings allows the administrator to select the VoIP codecs that are
enabled / disabled in the unit by dragging and dropping them into the
according areas. Within the enabled area, the order from top to bottom gives
the ranking in which the codecs will be offered. Supported codecs are G.711 u-
law and G.711 a-law, G.722, G.726, and G.729.
The Codec ptime override can be set to values between 10 and 100
milliseconds. Factory preset is 20 ms.
30