for what? Normal streaming or recording? For streaming 16 bits bitrate using 8 kHz sample rate is the only supported PCM format.
BTW It gives you the buffer size 320 bytes for 20 ms sample, which is normally used for converting into AMR.
On normal S60, only (ESampleRate16000Hz,EChannelsMono) and (ESampleRate8000Hz,EChannelsMono) parameters are acceptable.
On SendoX, only (ESampleRate22050Hz,EChannelsMono) is acceptable.
Because I heard that Nokia 6630 support Stereo output and higher frequency, who can give a test result?