[Freeswitch-users] fax, debuggin

[Robert Stevens]

Check out this doc from Audio Codes: https://copy.com/aiF9RZpbLZre, specifically ‘Table 1: Fax Relay Versus PCM Transfer’.  Its full of data about faxing in general.  g.711 faxes are extremely susceptible to jitter.  Theres not much you can do unless you use T.38 which can have a lot of redundancy built in.  I guess if you were a savant you could listen to the g.711 rtp stream from the spa but most of us can’t do this.. ;)


On Sep 8, 2014, at 10:31 AM, Michael Jerris <mike at jerris.com> wrote:

> Simply fax is not going to be reliable enough on g711 alone.  If you are doing g711 passthrough, there is not going to be any good way to debug the issues other than looking at rtp issues like jitter and loss.
> 
> Mike
> 
> On Sep 8, 2014, at 5:32 AM, Miha <miha at softnet.si> wrote:
> 
>> yes, i know that but a lot of costumers is used to fax machines :)
>> 
>> And that is way i am asking if there is any way to debug this.
>> 
>> tnx
>> 
>> Dne 9/8/2014 11:01 AM, piše Dušan Dragić:
>>> Well, with your current setup (passing g711 through freeswitch), you don't.
>>> You should consider building a fax server (the"fax to mail" thing :))
>>> with freeswitch to replace the ata/fax machine if at all possible.
>>> 
>>> On 8 September 2014 08:01, Miha <miha at softnet.si> wrote:
>>>> Hi,
>>>> 
>>>> no, we are just using g.711 as t38 is not widely supported in our country.
>>>> 
>>>> ok, but how to use "spandsp" is this not just for "fax to mail" thing?
>>>> 
>>>> br
>>>> miha
>>>> 
>>>> Dne 9/7/2014 2:17 PM, piše Dušan Dragić:
>>>>> Ah, right, I assumed we were talking about sending/receiving between fs and ata.
>>>>> 
>>>>> So Miha are you using T.38 (and on which leg) or G.711, as Brian asked?
>>>>> If you're using G.711 it's just another audio call to freeswitch and
>>>>> there's nothing fax specific to see.
>>>>> 
>>>>> On 5 September 2014 02:05, Michael Collins <msc at freeswitch.org> wrote:
>>>>>> That only works if spandsp's rxfax or txfax is being used.
>>>>>> 
>>>>>> Brian's question is the most important: is the SPA112 using T.38 or just
>>>>>> good ol' G.711?
>>>>>> 
>>>>>> -Michael
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> On Thu, Sep 4, 2014 at 2:57 PM, Dušan Dragić <dragic.dusan at gmail.com> wrote:
>>>>>>> MIha,
>>>>>>> do you have verbose fax log enabled, either globally in spandsp.conf.xml
>>>>>>> i.e.
>>>>>>> <fax-settings>
>>>>>>>    <param name="verbose" value="true"/>
>>>>>>>     ...
>>>>>>> </fax-settings>
>>>>>>> 
>>>>>>> or in the dialplan with variable fax_verbose=true ?
>>>>>>> 
>>>>>>> On 4 September 2014 09:47, Miha <miha at softnet.si> wrote:
>>>>>>>> Hi Michael,
>>>>>>>> 
>>>>>>>> the analog fax device is via some sip adapter(linksys spa112) registered
>>>>>>>> on
>>>>>>>> FS. I am dealing all the time with failed fax transsmisions and i do not
>>>>>>>> know how to debug this. In fs logs I can not see anything usefull. Do I
>>>>>>>> need
>>>>>>>> to set something for fax debugging?
>>>>>>>> 
>>>>>>>> tnx
>>>>>>>> miha
>>>>>>>> 
>>>>>>>> Dne 9/3/2014 7:16 PM, piše Michael Collins:
>>>>>>>> 
>>>>>>>> Where does FS fit into the path of the fax transmission/reception? If
>>>>>>>> you're
>>>>>>>> using the rxfax and txfax DP apps then the FS log will have lots of
>>>>>>>> stuff.
>>>>>>>> 
>>>>>>>> -MC
>>>>>>>> 
>>>>>>>> 
>>>>>>>> On Wed, Sep 3, 2014 at 1:39 AM, Miha <miha at softnet.si> wrote:
>>>>>>>>> Hi,
>>>>>>>>> 
>>>>>>>>> how to debbug fax issue on FS? I can do wireshark trace and that is
>>>>>>>>> all.
>>>>>>>>> Normaly signaling is in 99% ok, but is there any way to know what was
>>>>>>>>> wrong with fax transmission?
>>>>>>>>> 
>>>>>>>>> tnx
>>>>>>>>> miha
> 
> 
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