[Serusers] click to dial

hi,Jiri In my last click to dial letter, i said that it seems not to be implemented fully. this example does not work. The reason is use of REFER for third-party call-control has not been standardized . I thank after the call session is established , then it will need establish RTP channel to transport voice datas from web UA(caller) to another UA(callee), so i said it need RTP stack to establish RTP channel. you replyed: "It is in there and you don't need RTP." what's meaning? In files of click_to_dial and ser, i can't find any codes about establishing RTP channel ,you can tell me where or why don't need RTP?