Nanang, > Yes, it is supported, please check doxygen doc in > pjmedia/include/pjmedia-codec/passthrough.h for more info (the online > doc hasn't been updated yet). Thank you for your response. Support for G.729B when accessed through APS/VAS Direct assumes that the firmware running on the phone includes this codec... correct ? So, is it possible that there are Nokia phones running a version of firmware that does not include G729.B? Are there any messages generated in pjsip's log under such a circumstance ? Where can I find a list of firmware level Nokia E-series supported features? With some searching on google i found - Several posts on Nokia's forum where people are complaining about VAD not working when using APS/VAS - Nokia's datasheets do not indicate explicitly that G729B is supported when using APS/VAS Does PJSIP/PJMEDIA implement a VAD/DTX scheme in front of the G729 codec ? Thanks and Regards, Vikram.