[Users] Support for T.38

[Stephen Varga]

Max,

OpenSER does not get involved with the media stream, it just handles 
call setup and therefore does not generate FAX tones. It is up to the 
UAs to negotiate CODEC used for the call. In the example you provided of 
the call path, both the IP gateway and the PSTN gateway would have to 
support the T.38 specification. If one side does not support T.38 they 
will most likely use a normal voice CODEC to handle the FAX tones and 
FAX tones do not do well when compressed with voice CODECs.

Steve

Max Gregorian wrote:
> Hi,
>
> Does anyone know if OpenSER supports T.38 for Fax over IP?
> Or has anyone managed to get it to work?
>
> I did some quick tests and what I got was the destination Fax machine 
> rang,
> but the fax message did not arrive. I don't think the destination fax 
> picked
> up.
>
> Setup was:
>
> Fax (PC modem) -> IP Gateway -> OpenSER -> PSTN -> Fax machine
>
> Is it possible the Fax tones are not being properly generated by OpenSER,
> and so not being recognised by the Fax machine? (For reference, the 
> Gateway
> used is advertised as supporting T.38)
>
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