[Asterisk-Users] (no subject)

[Aaron Kenny]

Hello,

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.

Thanks for your time.

Aaron