[Freeswitch-users] FreeTDM and DAHDI+OSLEC/MG2 anyone?

Jeroen C. van Gelderen jeroeng at thegreek.com
Mon Jun 28 13:01:42 PDT 2010


Hi Moises,

Thank you. This is very helpful as it seems to detail the same problem. I
tested with both OpenZap and FreeTDM yielding the same results.

I think Anthony Minnessale is close when he writes:

"Maybe there are some new ioctls or something 
 they added for interop with OSLEC that we don't 
 know about."

Except that whatever changed in (the) DAHDI (API) seems to have broken all
echo canceling (MG2 and OSLEC) somewhere between DAHDI and FreeTDM/OpenZap.

Anthony also suggests:

"If you still have the problem the next step 
 would be to add some debugging code to the 
 ozmod_zt read and write functions to see if 
 it's sending data up to the app."

I'm going to see if my C-fu is up to doing that. Anybody know where the
debugging code should go for FreeTDM?

Lastly, the only semi-relevant Google find I did was this [1]:

"Make sure echotraining is disabled when using 
 Oslec - this is not supported and if enabled 
 will cause the channel to be silent (i.e. no 
 audio will pass through)"

In FreeTDM/OpenZap/FreeSwitch there doesn't seem to be an "echo training"
knob to twiddle.

Cheers,
-Slim

[1] http://www.rowetel.com/ucasterisk/oslec.html

--
Jeroen C. "Slim" van Gelderen
Olympic Sports Data Services
Email: jeroeng at thegreek.com
Phone: +1 876 953 6182 x128
________________________________________
From: freeswitch-users-bounces at lists.freeswitch.org
[mailto:freeswitch-users-bounces at lists.freeswitch.org] On Behalf Of Moises
Silva
Sent: Monday, June 28, 2010 10:04
To: freeswitch-users at lists.freeswitch.org
Subject: Re: [Freeswitch-users] FreeTDM and DAHDI+OSLEC/MG2 anyone?

This may be of help:

http://lists.freeswitch.org/pipermail/freeswitch-users/2010-March/055505.htm
l

Moises Silva
Senior Software Engineer
Sangoma Technologies Inc. | 50 McIntosh Drive, Suite 120, Markham ON L3R 9T3
Canada
t. 1 905 474 1990 x 128 | e. moy at sangoma.com

On Sat, Jun 26, 2010 at 8:57 PM, Jeroen C. van Gelderen
<jeroeng at thegreek.com> wrote:
Hi everybody,

I have a feeling I must be missing the obvious...

I've been trying to get echo canceling to work with Freeswitch/FreeTDM/DAHDI
but I have been failing miserably for days. When I enable echo cancellation
(MG2 or OSLEC) on a DAHDI/FreeTDM channel (FXS or FXO) that channel goes
silent.

In absence of better suggestions I was hoping to replicate someone's "known
working" configuration. Is anyone successfully running the following
combination:

- any x86 hardware
- any recent flavor Linux
- any recent version of DAHDI using FXO ports
- FreeSwitch/FreeTDM trunk from git
- OSLEC echo canceller (or MG2)
- (BONUS:) Xorcom Astribank with FXO/FXS ports.

I addition to much Googling I've tried most permutations of:
- CentOS 5.4, 5.5, Ubuntu 10.04 LTS, Elastix
- x86 and x64 single and multicore CPUs.
- Non-PAE kernels for 32-bit installs.
- DADHI from SVN (or -in case of Elastix- the built-in 2.2.0.2)
- MG2 and OSLEC echo cancellers
- Freeswitch from Git trunk

In each case everything configures fine to the point that Asterisk 1.6 will
function with echo cancellation enabled. So we know that DAHDI layer works.
But Freeswitch channels go silent when echo cancellation is enabled.

Puzzled,
-Slim

--
Jeroen C. "Slim" van Gelderen



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