[Asterisk-Users] SpanDSP - Squished Faxes

[Marcelo Pacheco]

Sure the TDM400P will never do V.90 modem. But I had some extremelly 
interesting results ...

Modem ---> TDM400P ---> Asterisk ----> TE405P ---> PRI E1 ISDN ----> PSTN ---> 
PRI E1 ISDN -> Cisco AS5300 RAS
I got 33.6kbps reliable connection

Crazy test follows.

Modem ---> PAP2-NA ---> Asterisk ----> TE405P ---> PRI E1 ISDN ----> PSTN ---> 
PRI E1 ISDN -> Cisco AS5300 RAS
I got 50.3kbps reliable connection after tweaking PAP2-NA, between the PAP2-NA 
and Asterisk, there's a FreeBSD NAT/QOS appliance.

Asterisk is on cheap but high quality hardware (Intel desktop mo-bo, Intel 
processor).

Final config:

PSTN ----> PRI E1 ISDN ----> TE405P ---> Asterisk ---> TE405P ----> AS5300 RAS

When I dial from an analog line, I'm getting the same performance we would 
from the ISDN hooked up directly to the AS5300...

Still need to test dozens of simultaneous modem calls. We still have the 
choice to have another AS5300 splitting the ISDN between the RAS and 
Asterisk, but that's our last resort. For now the production RAS is still on 
the other (to be deactivated ISDN).

Configure Asterisk E1 stuff well and it works real well. I really wasn't 
expecting results this good.

Marcelo Pacheco

Em Sex 24 Jun 2005 16:26, Brian West escreveu:
> > EASY there, Brian, easy...  There are some very smart cookies (and
> > me, but I'm
> > not a smart cookie) working on this.  It is rumoured (I have not
> > yet tested)
> > that 1.0.7 does NOT have this problem, and I KNOW I had it working
> > with HEAD
> > but that was probably back March or even Februaryish timeframe.
>
> The official word from digium is "TDM400P is not intended for use
> with analog modems or faxes.
> Thus, Digium will not support use of modems or faxes on the TDM400P."
>
> http://bugs.digium.com/view.php?id=4390
>
> covers the:
> Modem => TDM400P => Zaptel => * => Zaptel => TDM400P => Modem
>
> It works great with T1 boards just not the TDM400P.  And squished
> faxes are caused by frame slips.