[PLUG] Asterisk - echo with cisco 79xx handsets (resolved)

[Keith Lofstrom]

On Wed, Jan 11, 2012 at 01:14:02AM -0800, Keith Lofstrom wrote:
> Thanks everybody for the help so far on Asterisk issues.
> Here's what has helped:
....
> 4) I appreciate the suggestion of Digium's HPEC, and may end
> up using it, but it seems that the Kool Kids are using the
> open source "oslec" echo canceller instead of the default mg2.
> I haven't managed to get this to compile and load properly yet, 
> but eventually it will fall to the mighty hammer of "googling
> for error messages".  Hindered but not stopped by the name 
> migration from zaptel/zapata to dahdi.

I have everything working with oslec now.  I had to drop back 
to dahdi 2.3.0.1 (I was at 2.5.0.2), and the best instructions
were here:

http://www.bsmdev.com/Reference/Tech_20100001.html

There was two issues with the instructions.
When I rebuilt dahdi and started up, I got two error messages:

   Unrecognized garbage 'Reserved' in WCTDM/0/2
   ...

and 

   Running dahdi_cfg:  DAHDI_ATTACH_ECHOCAN failed on channel 1: Invalid argument (22)
                                                           [FAILED]

The first warning message was resolved by copying the newer version 
of /usr/local/share/perl5/Dahdi/Chans.pm  from the 2.5.0.3 source.
It wasn't serious, but it was ugly.  I don't have daughter cards on
on all the slots on the TDM800 card, and it /whines/ about it.

The second hard error was fixed by adding "dahdi_echocan_oslec"
in front of the configured "wctdm24xxp" in /etc/dahdi/modules.
Basically, the error message occurs because it does not know 
how to autoload oslec.


It would be nice to find an updated version of the instructions
that work with the very latest 2.6.* dahdi, but perhaps that
should wait until the "echo" code gets out of staging and into
the main kernel, in which case the dahdi code won't need patching.
If there are any decent kernel hackers reading this, they might
take care of the pending issues on that code and work with 
Greg K-H to accept it.

In any case, oslec is very nice ( imagine the French soldier 
from "Monty Python and the Holy Grail" rasping "vehhuh naahs")

Thanks again for the help.  I hope this message finds its way
to other struggling oslec users.

Keith

-- 
Keith Lofstrom          keithl at keithl.com         Voice (503)-520-1993
KLIC --- Keith Lofstrom Integrated Circuits --- "Your Ideas in Silicon"
Design Contracting in Bipolar and CMOS - Analog, Digital, and Scan ICs