Gentlemen, I'm writing for a question about T.38 and h245 requestMode. At par. D.5 of H.323 AnnexD, it is written: "either endpoint may detect fax tones (i.e. CNG or CED) or the presence of V.21 carrier and HDLC flags. Typical scenarios for facsimile call detection rely on the analysis of CNG calling tone and a response of the CED answer tone and/or the initiation of fax procedures using the V.21 carrier and HDLC flags. Note that in some implementations the presence of either CNG or CED are optional. Therefore, both endpoints should take an active role in order to properly detect fax." and "When using two unidirectional fax channels, the endpoint that detected the tone shall initiate the standard H.245 Mode Request procedure by sending a requestMode message to its remote counterpart" The question is: if both the endpoints detect the tone, both can send a requestMode and this can happen at the same time; in this case both will receive, other than send, a requestMode. How is solved this situation? Has one of them to accept the change and the other has to reject it, or both can accept the change? Is there a standard procedure to be applied in this case (based for example on the master-slave decision, or what else)? I know that one possible solution is to implement the application so that only the "receiving fax endpoint" (i.e. the one detecting the CED at his local analog interface) sends the requestMode, but this seems not being recomanded by AnnexD. Kind regards, Francesco