Ray Jackson schrieb:
> Luki wrote:
> 
>>>However, when I execute
>>>TxFax I see two g711 alaw packets going out for every one coming back, so my
>>>outbound throughput is around 160kbps now.  The second packet's payload
>>>looks similar to the first, almost like a duplicate.
>>>    
>>>
>>
>>I'm no expert, but I think that's the redundancy intrinsic to T.38.
>>Steve Underwood had a page on T.38 but it's gone... Google's cache:
>>http://72.14.253.104/search?q=cache:6vjemQ-5rCsJ:www.soft-switch.org/t38/ch02.html
>>  
>>
> I am far from an expert myself, but from my understanding the fax 
> conversation starts out as standard RTP voice traffic (G711) and then 
> switches to T.38 when the receiving gateway (usually) detects a fax tone 
> - at least, this is the way the Cisco 5400's seem to operate.  However, 
> my issue is that I am never actually switching over to T.38/UDPTL 
> transmission as the fax tone itself is not recognised and is coming 
> through as garbage to the other fax machine.  I was wondering if it was 
> possibly related to the 2 x alaw packets being sent where I would 
> usually expect to see just 1?  If there is some redundancy also built 
> into the initial RTP G711 conversation, I'm wondering if this can be 
> disabled somehow in the SpanDSP or OPBX code/config?
> 

I 've met the same issue (see also Bug #279).

Best regards

Hans
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