[asterisk-users] Asterisk 1.6.1.11 Fax

[Steve Underwood]

On 12/11/2009 03:33 AM, Kevin P. Fleming wrote:
> Cyprus VoIP wrote:
>
>    
>> Before posting my question, I analyzed the entire SIP negotiation and it
>> was fine. The problem began in the T.38 negotiation itself, after the
>> Asterisk's reINVITE. I don't have the old calls traces anymore, but I'll
>> make new ones tomorrow and post them here.
>>      
> The T.38 negotiation is part of the SIP negotiation, so that comment
> doesn't make a lot of sense.
>
>    
>> Regarding the MaxBitRate, is it possible to increase it to 14400 or is
>> 9600 the max allowed?
>>      
> It is controlled by the endpoint that is performing the T.38 negotiation
> in Asterisk, either an application or a channel driver (if the call is
> bridged to another channel). It can be set to any value allowed by the
> T.38 Recommendation, but it will only be set to values that the
> application actually supports. Increasing it is no way going to make
> your T.38 negotiation succeed if they are failing, nor will it make
> FAXes work if they are failing. It's purely an informational element.
>
>    
Something is wrong if Asterisk is sending:

a=T38FaxFillBitRemoval
a=T38FaxTranscodingMMR
a=T38FaxTranscodingJBIG

Spandsp supports T38FaxFillBitRemoval, but neither spandsp or Commetrex support the other two options. The Commetrex guys have said so in the FoIP working group.

Regards,
Steve