[Serusers] G729 codecs --help

Hi users, I have one doubt here please try to give some information to me. I am using SER-0.9.6 with mediaproxy-1.7.2 and for testing purpose i am using grandstream adapter handytone-496 If i make changes in codecs in grandstream that it should only use g729 codec --the call is not implemented "here what i want to know is does grandstream support G729 codec or the adapter compress the voice in G729 format when we select g729"? if later is correct , so we must have to implement g729 codec in SER or in mediaproxy so how we can do that? if i put G711 only,- the call is implementing or other wise the call cannot be made by the SER. so please give me some information regarding this :-( Thank You. Regards, Ravi.