[asterisk-users] T.30 Fax session error: Received bad response to DCS or training

[Lee Howard]

On 07/01/2012 01:46 AM, Petros Moisiadis wrote:
> Hello,
>
> On http://pastebin.com/AP5GBWUR you may see an excerpt from asterisk
> full log that includes a failing fax sending session. As you can see in
> line 328, the transmission fails with error "Received bad response to
> DCS or training". It seems that something goes wrong along the lines 315
> to 320, but I can't figure it out. Perhaps somebody with enough
> experience with the T.30 protocol can understand what is happening. What
> does this DCN 'ff 13 fa' response mean? I would highly appreciate any
> tip on how to get more info about this error or workaround it.
>
> I' m using asterisk 1.8.11.1, as does the other end.

DCN is disconnect.  So DCN in response to DCS means that the receiver 
didn't like something about DCS, TCF or possibly TSI so much that it 
decided to abort the fax by disconnecting after announcing it.

Thanks,

Lee.