<div>I am having classic "frame slip" symptoms on 4 different systems
with 4 different providers (all full PRIs, Qwest, XO, Xspedius, and First
Digital are the providers). By classic I mean pages cut short. I do not hear
clicks on calls however, and faxing from a fax machine plugged into the asterisk
box via an fxs port (no VoIP) faxes just fine through the PRI. Also, faxing
directly from said fxs port to spandsp (IE not traversing the PRI) works
wonderfully. <br><br>I do not see any missed interupts on any of these systems,
the digium cards (tdm400's for fxs ports, and te110p's for PRI termination) are
not sharing IRQs with anything else, and they are not on the same IRQ themselves
IE, they are totally isolated in the IRQ space. <br><br>Generally shorter faxes
(IE < 3pages) get through just fine, however anything longer than that will
have a failed page about 50% of the time, and anything over 10 pages always has
a failed page (except on Xspedius, which has about a 50% fail rate above 10
pages). <br><br>I have searched everywhere, and the "answer" to this problem seems to be frame slips on the PRI however, all 4 systems are set to sync with
the PSTN connection, I'm not running X on any of these systems, (although
turning X on doesn't negatively effect them either... IE I get the same number
of errors with X running or not). Also, there is no mention anywhere of a "fix" or even anything to try to reduce or eliminate frame slips.<br><br>I recompiled spandsp to log the audio files, does anyone know what type of file that is? can I listen to it? Or is Steve the only one who knows how?
<br><br> how come a standard fax machine can fax over
this PRI connection just fine, but spandsp cannot use it? If frame slips are
occurring, shouldn't they break faxing on the machine as well? If not, the machines
must be doing some error checking or something that spandsp does not currently
support so that they can deal with frame slips. Does spandsp do any sort of
error checking/page resend requesting? What would it take to make spandsp more
robust in this regard? Or is it just something that can't be overcome in
software, but that hardware modems in fax machines can handle? I am more than
willing to help out any way I can (including code, although I'd need a little
help getting up to speed on the code) to get spandsp working on these boxes.
<br><br>Is there anything else to try? <br><br>Basically all of the posts I've
been able to find say "Don't share IRQs, turn off X, and make sure the PRI is
configured properly", well I've done all of that. Do I just have 4 bad PRIs
that can't keep time? These systems are deployed as a test solution for fax-email, they are the only 4 I've setup to use spandsp so 100% of the systems I have installed show this problem, and they
show it across telecom vendors all other things being equal (exact same
hardware, exact same OS, exact same asterisk, spandsp, etc versions asterisk
1.2.4, zaptel 1.2.4, libpri 1.2.2, spandsp 0.0.2pre25). I have tried later
versions of asterisk, zaptel, and libpri, but not a 0.0.3 version of spandsp. I
have sent faxes from many different fax machines, all show the problem.
<br><br>I have attempted to run a utility I found
called ztclock... suprisingly of the 4 pri's the "best" as far as spandsp
results are concerned is Xspedius (of the 4 it is the only one that ever
receives 10+page faxes without error, still only about 50% of the time, but the
other 3 never receive more than 10 pages without failing a page). However,
according to ztclock it is the worst as far as frame slips are concerned. Here
are the results of Qwest vs Xspedius. <br><br>Qwest PRI:<br>ztclock - clock
source accuracy test (3 passes)<br><br>Flushing input buffer...<br>Flush
Complete.<br><br>Test is approximately 3 minutes. Please wait...<br><br>483328
samples in 60.416021 sec. (483329 sample intervals) 99.999794%<br>483328 samples
in
60.416041 sec. (483329 sample intervals) 99.999794%<br>483328 samples in
60.416097 sec. (483329 sample intervals) 99.999794%<br><br>Estimate 8 frame
slips every 483.328003 seconds.<br><br><br>Xspedius PRI:<br><br><br>ztclock -
clock source accuracy test (3 passes)<br><br>Flushing input buffer...<br>Flush
Complete.<br><br>Test is approximately 3 minutes. Please wait...<br><br>483328
samples in 60.416018 sec. (483329 sample intervals) 99.999794%<br>483328 samples
in 60.416037 sec. (483329 sample intervals) 99.999794%<br>483328 samples in
60.514997 sec. (484120 sample intervals) 99.836136%<br><br>Estimate 8 frame
slips every 0.610263 seconds.<br><br>The other 2 PRIs show ztclock results
similar to Qwest, 8 frame slips every 400-500 seconds. <br>Any help or
suggestions would be greatly appreciated. <br><br>Thanks for your time,<br></div>
<div><span class="sg">Tom Christensen<br></span></div>