Mitel T.38 Fax Issues

[ralph]

I have a customer using T.38 over their WAN.
The fax machine has issues where it frequently (maybe sometimes) doesn't get the entire fax.  It may only get 1/2 of the 1st page.

Does anyone know of any logs that will show T.38 issues?

Ralph

[ralph]

Found some logs in the maint logs but it's not useful.

In the same building other faxes work fine. 
Customer says this is the 3rd fax.

Next question is: is there a way in the 3300 to slow the faxes down?  The thought being that the sender is sending too fast for what we can accept.

Ralph

[wiseguy]

Wireshark is the only way of locating any issue. Are you sure that there no compression of any sort on that connection. Assuming that you have referred to the default FAX Zone settings in the 3300 it should request 9600 or 14400 as speed.

[martyn]

This sort of sounds like a compression issue, but a wireshark trace would be the best way to know for sure.

What kind of % fail rate is actually occuring, and is there a common machine or number that it is failing with?

[ralph]

There isn't any compression going on, I've verified that.
They've replaced the fax machine that has the most problems but it also happens with others.
Call Q logs show everything looking just fine - no packet loss and almost no jitter.

I was about to send a tech out to replace a DSP but then the customer called and said it's working much better now.  (?)
So I haven't been able to nail it.

As for %, I was trying to send a 10 page fax and it was failing almost 100%.   Then it's ok.   Still leaning toward a bad DSP.

Ralph

[Mattmayn]

I don't remember where in the programming it is but there is a way to limit the baud rate in the 3300. It has been a while since I messed with their T.38.

[ralph]

Yes.  Played with all those settings.   It's under fax zones

Ralph

[martyn]

Starting to sound like a DSP issue then. Is there a DSP or DPS II card in the box?
There is a similar problem here at the moment where the DSP card isn't cutting it and has to be replaced with a DSP II card.

[ralph]

I'll have to double check the DSP version.   I stood down once they said it was working.

Ralph

[Mattmayn]

I think a DSP II is required for T.38. I don't think the normal DSPs are capable.

[wiseguy]

An easy test to see if this is caused by the DSP card would be to connect the fax through a T38 capable SIP/Analoge converter.