Hello guys, I installed mod_gsmopen. When testing incoming call, it hangs up with this error message INCOMPATIBLE_DESTINATION. I understand this is a codec negotiation issue. Looking at the CDR - the gsmopen presented L16 8000 in the SDP. By default, FS does early negotiation. Snippet of my internal sip_profile: <param name="inbound-codec-prefs" value="$${global_codec_prefs}"/> <param name="outbound-codec-prefs" value="$${global_codec_prefs}"/> <param name="rtp-timer-name" value="soft"/> <param name="rtp-ip" value="$${local_ip_v4}"/> <param name="sip-ip" value="$${local_ip_v4}"/> <param name="presence-privacy" value="$${presence_privacy}"/> <param name="inbound-codec-negotiation" value="generous"/> Take note: there is no disable-transcoding parameter which I understand FS is transcodind. In vars.xml: <X-PRE-PROCESS cmd="set" data="global_codec_prefs=G7221@32000h,G7221@16000h ,G722,PCMU,PCMA,GSM"/> <X-PRE-PROCESS cmd="set" data="outbound_codec_prefs=PCMU,PCMA,GSM"/> I tried to add L16 at the end of global_codec_prefs which is unnecessary, isn't it? But it didn't work, too. Finally, I added L16 in the softphone, it worked. I have installed gsmopen before and it worked (transcoding) with IP phones. Is there anything I may have missed? I appreciate for any leads. Thank you, /Nandy