progress update

[DavidRowe]

Hi Guys,

I was wondering if anyone had progressed the work at all, for example
Asterisk chanel driver mods or Atmel software?

I havent done anything yet, but will get more heaviliy involved in the
2nd half of 2007 once the IP04 IP-PBX I am working on is in
production.

Thanks,

David

[Brian Mohr]

Hey David,

I spent the better part of last week digging through and modifying chan_oss - it was rewarding!  Essentially I am at the point where I am working on rewriting the "setformat" function.  It's very specific  to Soundcard/DSP formats - setting variables like SNDCTL_DSP_GETOSPACE, etc...   it just needs to be rewritten to push out data at the proper frame and queue size (I think).

What I was able to do was confirm that I can infact pipe audio through rs232.  I modified chan_oss enough so that I can use the console commands from the CLI to make and receive (inaudible) calls.  I piped the demo congrats IVR from the console of one asterisk server to the /dev/dsp device of a serially connected laptop - the audio was completely garbled but the duration and bursts of silence/noise corresponded with the IVR (I think).  It was very exciting.  I also tried random experiments piping to /dev/dsp, and flat files.  I could make calls from a SIP phone- to the Ast box - to the console (chan_oss) - and definitly hearing garbled audio from the laptop (via /dev/dsp) - again, much fun.

So, overall, I've made a bit of progress testing and am at the point where I simply need to finish writing the setformat function in chan_oss.c.

I am not sure how much time I'll be able to spend on that this week - but I will keep the group updated.

Thanks
Brian

[DavidRowe]

Thanks for the update Brian. I have just received a couple of PICs
with Ethernet capability built in, samples from Microchip that took
about 4 weeks to arrive. I will start messing with them in the 2nd
half of this year. Using Ethernet for the ATA connection will mean it
can be placed anywhere, ie a long way from the router. I am still
keen on exploring the USB and RS232 options, this is just another
posibility.

Also Tim has made good progress with a low cost 8 port FXS project:

http://www.rowetel.com/blog/?p=32

http://blog.mithis.net/archives/uni/41-cfxs-all-done

I think with some careful assembly code and celever low-MIPs
algorithsm for echo cancellation we might be able to get this to run
on a router.

Cheers,

David

[Tim Ansell]

On Fri, 2007-05-25 at 16:46 -0700, DavidRowe wrote:
> Thanks for the update Brian. I have just received a couple of PICs
> with Ethernet capability built in, samples from Microchip that took
> about 4 weeks to arrive. I will start messing with them in the 2nd
> half of this year. Using Ethernet for the ATA connection will mean it
> can be placed anywhere, ie a long way from the router. I am still
> keen on exploring the USB and RS232 options, this is just another
> posibility.

Just a couple of thoughs about using this chip.

If you want good efficiency, don't try to do TCP/IP. I would recommend
instead packing raw Ethernet frames. This means you need slightly more
code on the router side, but it will have less overhead.

For a single line device, it may be better to go the TCP/IP route - but
if I do a Ethernet version of my 8 line device I will probably have to
go the Ethernet frame packing route.

> Also Tim has made good progress with a low cost 8 port FXS project:
>
> http://www.rowetel.com/blog/?p=32
>
> http://blog.mithis.net/archives/uni/41-cfxs-all-done
>
> I think with some careful assembly code and celever low-MIPs
> algorithsm for echo cancellation we might be able to get this to run
> on a router.
>
> Cheers,
>
> David

I have to concentrate on my exams now - but I will get back to things in
about a month.

Tim Ansell