[asterisk-users] dahdi wcb4xxp and fax

[Olivier]

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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