Should avoid buzzing on GTA02a5 devices, while utilizing the Om2008.12
echo cancellation feature (ie. volumes on okayish level, not too quiet).

Updated:
some buzz might (/will) now occur, what was changed was:
Mono playback 103 -> 110
Mono Sidetone Playback Volume 4 -> 5

This was done because of a few complaints of too low voice volume.