[Asterisk-Users] (no subject)

[Rich Adamson]

> I am having some problems with faxing in asterisk.  I have a TE100P
> which is taking my PRI.  This seems to be working fine.  I also have a
> TDM400P with 2 FXS.  Again card seems to be working fine, I can dial
> from phones attached to these to ports and everything seems to work
> fine.  I have 2 DID's for my two fax machines that dial the Zap port
> for the FXS on the TDM400P.
> 
> The problem comes in when I attempt to send or recv a fax on a fax
> machine attached to the TDM400P.  Most of the time the fax will
> terminate part way through the transmission, however it will
> occasionally go through just fine but slow.
> 
> I trying to resolve the situation I have tried many things.  I first
> removed echo cancellation on both my FXS ports and my PRI.  That
> didn't seem to have an effect at all other than more echo on voice
> calls.  I do notice on my asterisk console that it seems to be
> disabling the echo cancellation when it hears the fax tones anyway.
> 
> I then contact Digium, which won't official support faxing of course,
> but gave me some things to check.
> 
> 1.  No interrupt sharing.  I disabled all unnecessary devices, like
> USB, etc, and had verfiied that the Digium hardware was on all on its
> own IRQ.  This seemed to have not effect.
> 
> 2.  Disable Hyperthreading.  I did this and it seemed to have no effect.
> 
> 3.  Ensure your not getting any NMI's.  Which I did, and I was not
> accumulating NMI"s..
> 
> 4.  Run"hdparm -t /dev/[Hard Drive Device]" and notice if you hear
> crackles, pops, or loss of audio.  I did get substantial interference
> with the audio when running this.
> 
> Digum had me run the zttest application, which showed every couple of
> interations I would get a reading of 99.3 or 99.4 where they say
> anything below a 99.89 is bad.
> 
> I can fax from FXS to FXS on the same card just fine.  Which I think
> is an interesting point.  Maybe it has to do with data passing across
> the bus to the t1 card?
> 
> The only recommendation that Digium had left was to run the Hard Drive
> in DMA mode.  Since I currently have a SATA drive in this system this
> isn't possible.  I am willing to try running a PATA style drive in the
> system so DMA can be turned on.  Number 4 above seemed to agree that
> it is possibly the SATA HD causing I/O issues on the sytem.
> Installing a new HD will be a time consuming process so I thought I
> would post to the list first to see if anyone else had any
> ideas/experiences.

It's highly unlikely that you can do anything more to resolve the 
problem.

It is the same problem that many of us have been discussing on this
list for months regarding the TDM card and missed frames. I can say
that folks are trying to narrow down the root cause and hopefully
will have a fix in the next several weeks.