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Checking for FAX


Gunny
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Hi all,

 

I create an IVR node with DTMF match list = !F!201! !T!250!

When a call arrives, if is a FAX, go to 201, else go to 250.

 

If I send a fax, the rule doesn't work, the call always go to 250.

What's wrong? There is something that I need to know?

 

Thanks in advance.

 

Giorgio.

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I create an IVR node with DTMF match list = !F!201! !T!250!

When a call arrives, if is a FAX, go to 201, else go to 250.

 

If I send a fax, the rule doesn't work, the call always go to 250.

What's wrong? There is something that I need to know?

 

Hmm. The pattern looks right to me. Do you see something like "[6] Received DTMF F" in the log file?

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Hmm. The pattern looks right to me. Do you see something like "[6] Received DTMF F" in the log file?

 

Thanks for the reply.

... no, I don't see "received dtmf f", i get only:

 

[9] 20081021125333: DTMF: Power: 0 0 2 0 2 0 0 1 0

[9] 20081021125333: DTMF: Power: 1 2 0 0 0 2 0 0 1

[9] 20081021125333: DTMF: Power: 0 0 0 0 0 0 1 1 1

[9] 20081021125333: DTMF: Power: 0 2 0 0 0 2 0 0 1

.........

 

but nothing marked as "[6] received".......

 

I try also a call between 2 extensions (2 sip phone, snom and grandstream), once the call is established, I send a DTMF (only to try...), in the log i get the same messages, nothing like [6]...., only [9].....

 

Giorgio

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... no, I don't see "received dtmf f", i get only:

 

[9] 20081021125333: DTMF: Power: 0 0 2 0 2 0 0 1 0

[9] 20081021125333: DTMF: Power: 1 2 0 0 0 2 0 0 1

[9] 20081021125333: DTMF: Power: 0 0 0 0 0 0 1 1 1

[9] 20081021125333: DTMF: Power: 0 2 0 0 0 2 0 0 1

.........

 

but nothing marked as "[6] received".......

 

I try also a call between 2 extensions (2 sip phone, snom and grandstream), once the call is established, I send a DTMF (only to try...), in the log i get the same messages, nothing like [6]...., only [9].....

 

Okay, at least we now know that the problem is the inband fax tone detection. Hmm. Maybe you can get a Wireshark trace, send me a private mail with a link where we can download it and then find out what the problem is. Lets see if we can detect the tone...

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I send the mail, could you confirm that arrives? .... it's the first mail from the forum....

 

Yes, got it. We run this through the detector and it does detect the tone. Gain setting was set to 512 ("dtmf_gain"), but I guess that is the same for you (check the pbx.xml file to verify). So the tone detection logic is not the problem here. Did you try this in the auto attendant? Does the auto attendand send the call to the FAX extension? Maybe there is something in the IVR node that is the problem.

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Yes, got it. We run this through the detector and it does detect the tone. Gain setting was set to 512 ("dtmf_gain"), but I guess that is the same for you (check the pbx.xml file to verify). So the tone detection logic is not the problem here. Did you try this in the auto attendant? Does the auto attendand send the call to the FAX extension? Maybe there is something in the IVR node that is the problem.

 

Yes, the dtmf_gain is set to 512.

The first test was on IVR, now we test on AutoAttendant.

There is always the problem.

 

We do other tests:

- install ZOIPER under pbxnsip (ext 190)

- install ZOIPER on my PC in OTHER LAN than Pbx, logged DIRECTLY on the provider, this only to try send fax.

- PBX redirect ALL the incoming call to ZOIPER (190)

 

- If we send a fax with a STANDARD FAX, zoiper didn't recognize that it's fax

- If we send a fax with the ZOIPER client on my PC, zoiper recognize that it's fax

 

With the Standard fax, we try with:

- VOIP line

- Telecom line

- External service

none works......

 

What could be?

Why your detector works?

...? :-)

 

Giorgio

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Yes, the dtmf_gain is set to 512.

The first test was on IVR, now we test on AutoAttendant.

There is always the problem.

 

Well, the PBX is not directly involved in the FAX. Regarding FAX, it does only two things. First, it detects the FAX tone. This is like a DTMF tone, and this seems to work (at least using the file that you sent us). Second is the switch to T.38. This step is neccessary to make sure that FAX data does not get lost. If you keep the calls in the LAN then there is usually no problem. However if you are using a service provider in the Internet, and that service provider does not support T.38, then it is almost impossible to send FAX. There are always a few packets that get lost when sending FAX over the Internet, and that screws up FAX.

 

One more thing comes to my mind: Did you set "inband detection" (admin settings) to "on"?

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Well, the PBX is not directly involved in the FAX. Regarding FAX, it does only two things. First, it detects the FAX tone. This is like a DTMF tone, and this seems to work (at least using the file that you sent us). Second is the switch to T.38. This step is neccessary to make sure that FAX data does not get lost. If you keep the calls in the LAN then there is usually no problem. However if you are using a service provider in the Internet, and that service provider does not support T.38, then it is almost impossible to send FAX. There are always a few packets that get lost when sending FAX over the Internet, and that screws up FAX.

 

One more thing comes to my mind: Did you set "inband detection" (admin settings) to "on"?

 

 

Yes, I set Inband detection to ON.

In my wireshark file, why I don't get "[6] Received DTMF F".......

I'm a software developer.... so I REALLY don't understand, if the PBX receive the DTMF (as wireshark show)... why the software didn't understand the tone?

... if tone=xxxx then DTMF ..... ;-)

 

My provider switch ALL THE TONE..... and wireshark show that.

My test with zoiper was not on the lan, the Zoiper that SEND the fax was connectet directly to the sip provider.

We would sell to our customers (we are voip provider) something like "unique number", so the customer can receive fax and call on ONE number, but if the pbx didn't get the fax tone I can't switch the call to a fax extension and pbxnsip become a "normal" pbx.

 

Thanks, Giorgio

 

PS I send you also a private e-mail...

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