[asterisk-users] modem through Zaptel/Digium?

[Dave Fullerton]

Greg Woods wrote:
> This is just a low priority curiosity question because I have a usable
> workaround.
> 
> I have  Digium card that uses the Zaptel driver (can't get to my home
> machine right now to get the exact model, but it probably doesn't
> matter). It's a card with one POTS line and three extension hookups. I'm
> using Asterisk 1.4 and Zaptel 1.4.7 . 
> 
> One of the extension ports is connected to a modem on another computer.
> This is a FAX modem that works well; I have * programmed to detect
> incoming faxes and route them to this modem, and it works seamlessly. I
> can also send outbound faxes with no problem.
> 
> The curiosity is that this modem does not work for dialup unless I
> bypass the * server and connect it directly to the wallplate, then it
> works fine. I don't see why it would be able to detect carrier and
> negotiate with a fax machine through * and Zaptel, but not with a dialup
> server.
> 
> --Greg

I think asterisk has the ability to detect fax tones and disable echo 
cancellation for those calls. I don't know if that is the case with a 
regular modem call. I'd check to make sure that echo cancellation is 
disabled on the extension the modem is plugged into. The only other idea 
is to try connecting at a lower speed (I would think this would happen 
automatically though).

-Dave