Hi, I need to have the hability to negotiate the codec in a session (using proxy media or bypass media), unfortunally I've been unable to achive this due the documentation that I've found about it's vague. I've already tried using "absolute_codec_string" and everything that says in http://wiki.freeswitch.org/wiki/Codec_negotiation but it seams to ignore it when the media is in "bypass media" or "proxy media". I need to configure the FS as a SBC or as a pseudo proxy (I already know that FS is not intend to do it, but in the documentation says that it can). I've also tried to manually modify the SDP using: <param name="inbound-late-negotiation" value="true"/> And updating variables "switch_r_sdp" and "switch_l_dsp" but it also seams to ignore it. Here is the config: Endpoint1-->FS-->SWITCH-->FS-->Endpoint2 What I need, is to offer to the SWITCH only the codecs defined for Enpoint1 (ie. G729) and when the SWITCH send the INVITE to FS again, only offer the codecs available for Endpoint2. Eventually the SWITCH will do the transcoding. So, here is my question, is there any way to achive this? (Handle the invite codecs in bypass or proxy media), if so, is there any example to follow? o can you give a tip? Thanks in advance, Regards