G.729 Annex-B is a high complexity algorithm, and G.729A Annex-B is a medium complexity variant of G.729 Annex-B with slightly lower voice quality. The difference between the G.729 and G.729 Annex-B codec is that the G.729 Annex-B codec provides built-in IETF voice activity detection (VAD) and Comfort Noise Generation (CNG).
Adore Softphone comes with G.729 codec.