[asterisk-users] Using voice modem as poor man's FXO in Asterisk 1.8

[Stuart Longland]

Hi all,

I've tried researching this, and so far, have struggled to find any
contemporary information on the issue, so I do apologise if asking this
irritates people who have answered this before.

I have managed to set up Asterisk 1.8 on the web server here.  I have
two softphones (Ekiga) able to communicate with it.  So far so good. 
I'm now curious to see if I can link it with the PSTN phone line here.

The web server in question is an Intel Atom system with a Mini-ITX
motherboard.  Its one and only PCI slot is occupied by a PCI ethernet
card.  So FXO card is not an option even if it were within budget.

My options therefore look to be an external FXO device of some
description (Ethernet or USB), or to use a voice modem.  I fear external
FXOs are going to be even more expensive than internal FXO cards.

Now, I have here an old Maestro JetStream 56k modem here that does
amongst other things, voice comms, and I have used it in the past as a
telephone by plugging a headset into the front of it (and it was full
duplex too if I recall correctly).  I have also used it as an answering
machine, with the audio being transmitted digitally over the RS232
link.  So that to me suggests it is possible to get audio in to and out
of the modem, either via a sound card or using the serial port.  The web
server has a sound card too (hard not to buy a motherboard with one
these days).

Apart from the lack of any hardware signal processing, it seems all the
components are there.  The server isn't particularly heavily loaded, and
thus I see no reason why the machine wouldn't theoretically be able to
handle the DSP in software … I've seen lesser hardware do quite
sophisticated DSP in real-time.

Now, I've hunted high and low for where this is configured.  Some
mailing list threads point me to the nonexistant
/etc/asterisk/modems.conf.  One points me to /etc/asterisk/phone.conf,
but nothing there jumps out at me as being an obvious means for
configuring a modem — nor can I find where it's documented on the
Asterisk wiki.

Where abouts should I look for documentation on configuring these modules?

Regards,
-- 
Stuart Longland (aka Redhatter, VK4MSL)      .'''.
Gentoo Linux/MIPS Cobalt and Docs Developer  '.'` :
. . . . . . . . . . . . . . . . . . . . . .   .'.'
http://dev.gentoo.org/~redhatter             :.'

I haven't lost my mind...
  ...it's backed up on a tape somewhere.