[Asterisk-Users] RxFax - tiff problem

[Steve Underwood]

Hi,

If the problem on the PSTN cside, you need to ensure your E1/T1 is 
synchronsied to the PSTN. They will not synchronise to you. Look in your 
zaptel.conf, and ensure it is set to treat your E1/T1 as the primary 
clock source.

Regards,
Steve


Snezhana Bekova wrote:

> Hi Steve,
> thanks very much for your answer!
>
> It is unclear to me if this is a clock problem or a network problem? 
> (the traffic comes from some Cisco VoIP equipment at our operator's 
> side and passes a few 100Mbit switches on fiber).
>
> If it is a clock problem, what is to be done? Do we need to syncronise 
> the clock of the asterisk machine at our side to its hardware clock in 
> some way (how?) or is the problem at the operator's side?
>
> Snezhana Bekova
>
>
> Цитат на писмо от Steve Underwood <steveu at coppice.org>:
>
> > Hi Snezhana,
> >
> > Looking at the audio file, there are frame slips. That is, a clock
> > synchronisation problem, or a machine missing interrupts has caused one
> > or more audio samples to be lost. Fast modems (anything faster than
> > 1200bps basically) cannot cope with even a single lost sample.
> >
> > See http://ww.opencall.org/faq/x26.html and
> > http://ww.opencall.org/faq/x29.html
> >
> > Regards,
> > Steve
> >
> >
> > Snezhana Bekova wrote:
> >
> > > Hello,
> > > We use tiff version 3.5.7-2 and spandsp-0.0.2pre3 with asterisk
> > > version 1.0 on debian unstable. I have posted for our problem wtih
> > > fax. RxFax works and we receive faxes, but the tiff file is sometimes
> > > malformed although the fax seems to be received correctly. Our
> > > asterisk server receives calls and faxes from a mobile operator. We
> > > are connected to their Cisco router which connects to our asterisk
> > > over VoIP that goes inside a Vlan over 100Mbit fiber which passes a
> > > few switches. We move asterisk to other server, so it is powerful
> > > enough - it is under load of about 0.01 and CPU load 1% - 2%. So the
> > > problem is not the server.
> > > Maybe the problem is on the VoIP channel, but we cannot prove it.
> > > You can see at http://sbekova.cyberbg.com/fax/ a new example of a
> > > received tiff file, some audio log files and debug log.
> > > Are the switches and/or routers changing the packet order or is there
> > > something else?
> > > Thanks in advance.
> > >
> > > --
> > > Snezhana Bekova
> > >
> > >
> > 
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