asterisk users - Feb 2009 - dahdi wcb4xxp and fax

Hi all,

I wanted to switch from my current setup (mISDN) to the native dahdi with
b410p support (wcb4xp). All works fine for normal phone calls but not for
faxing. Faxes are distorted, if arriving at all, and hylafax logs the usual
bad stuff (HDLC frame not byte-oriented.)

Our setup uses a digium b410p card with asterisk 1.6, latest libpri and
dahdi, hylafax with iaxmodem, and all this on 1 machine.

chan_dahdi.conf contains:
faxdetect=both

When receiving a fax call, hylafax (iaxmodem) answers the call after the
obligatory wait of 3 seconds (fax detection) but to me it seems that echo
cancellation is still being done.

Any pointers on this or workarounds? We're back to our old misdn setup for
now ;)

Here's some output from "dahdi show channel 1" (the one that had
the fax
connection going), i cut out some non-related stuff :
*CLI> dahdi show channel 4
Signalling Type: ISDN BRI Point to Point
Owner: DAHDI/4-1
Real: DAHDI/4-1
Callwait: <None>
Threeway: <None>
Confno: -1
DSP: yes
Busy Detection: no
TDD: no
Relax DTMF: no
Dialing/CallwaitCAS: 0/0
Default law: alaw
Fax Handled: yes
Pulse phone: no
DND: no
Echo Cancellation:
        128 taps
        (unless TDM bridged) currently ON
PRI Flags: Call
PRI Logical Span: Implicit
Actual Confinfo: Num/0, Mode/0x0000
Actual Confmute: No



Regards,
stoffell
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stoffell wrote:
> I wanted to switch from my current setup (mISDN) to the native dahdi 
> with b410p support (wcb4xp). All works fine for normal phone calls but 
> not for faxing. Faxes are distorted, if arriving at all, and hylafax 
> logs the usual bad stuff (HDLC frame not byte-oriented.)
Make sure that you're using the latest mISDN drivers.

Thanks,

Lee.

2009/2/25 stoffell <stoffell at gmail.com>
> Hi all,
>
> I wanted to switch from my current setup (mISDN) to the native dahdi with
> b410p support (wcb4xp). All works fine for normal phone calls but not for
> faxing. Faxes are distorted, if arriving at all, and hylafax logs the usual
> bad stuff (HDLC frame not byte-oriented.)

What about outgoing faxes ?
>
>
> Our setup uses a digium b410p card with asterisk 1.6, latest libpri and
> dahdi, hylafax with iaxmodem, and all this on 1 machine.
>
> chan_dahdi.conf contains:
> faxdetect=both
>
> When receiving a fax call, hylafax (iaxmodem) answers the call after the
> obligatory wait of 3 seconds (fax detection) but to me it seems that echo
> cancellation is still being done.

Theory is that any echo canceller hearing a 2100Hz fax signal would halt
itself, so I wouldn't search in that direction first.

Have you tried native 1.6 sendFax, receiveFax ?
Maybe it would improve fax performance.
>
>
> Any pointers on this or workarounds? We're back to our old misdn setup
for
> now ;)
>
> Here's some output from "dahdi show channel 1" (the one that
had the fax
> connection going), i cut out some non-related stuff :
> *CLI> dahdi show channel 4
> Signalling Type: ISDN BRI Point to Point
> Owner: DAHDI/4-1
> Real: DAHDI/4-1
> Callwait: <None>
> Threeway: <None>
> Confno: -1
> DSP: yes
> Busy Detection: no
> TDD: no
> Relax DTMF: no
> Dialing/CallwaitCAS: 0/0
> Default law: alaw
> Fax Handled: yes
> Pulse phone: no
> DND: no
> Echo Cancellation:
>         128 taps
>         (unless TDM bridged) currently ON
> PRI Flags: Call
> PRI Logical Span: Implicit
> Actual Confinfo: Num/0, Mode/0x0000
> Actual Confmute: No
>
>
>
> Regards,
> stoffell
>
>
>
>
>
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