VoIP Mailing List Archives

[greg at gregandeva.net]

I previously posted about this problem and received suggestions
involving turning off echo cancellation. As far as I can tell, echo
cancellation is already disabled on this channel, so I'm back.

What I've got is a small home setup with a single four-port Digium card:

Module 0: Installed -- AUTO FXS/DPO
Module 1: Installed -- AUTO FXS/DPO
Module 2: Installed -- AUTO FXS/DPO
Module 3: Installed -- AUTO FXO (FCC mode)
Found a Wildcard TDM: Wildcard TDM400P REV I (4 modules)

One outgoing Qwest line, three internal extensions. I also have a couple
of Snom SIP phones and X-lite soft phones on Mac, Linux, and Windows
boxes, and a VOIP line via Teliax, but the soft phones and VOIP line are
used only rarely. One of the internal extensions goes to a modem on a
Linux desktop. This desktop is able to send and receive faxes just fine.
If I have receive fax mode enabled on the desktop, then incoming faxes
are automatically routed to this box by Asterisk and it works great.
Outgoing faxes are also no problem.

The problem is that PPP dialout does not work; pppd eventually fails
with "NO CARRIER". Dialout works fine if I connect the modem straight
through to the wall plate, the problem only happens when the modem is
connected through Asterisk and the Digium card. The same modem and
connection through which faxing works fine. (For completeness, I also
tried the dialout via the Teliax line, but that didn't work either; I
didn't really expect that it would).

Here is my zaptel.conf file:

fxoks=1
fxoks=2
fxoks=3
fxsks=4
loadzone=us
defaultzone=us

Channel 4 is obviously the Qwest line, channel 1 is the desktop modem.

Here's zapata.conf:

[channels]
usecallerid=yes
hidecallerid=no
callwaiting=no
threewaycalling=yes
transfer=yes
echocancel=yes
echotraining=yes
immediate=no

; house phones
context=internal
signalling=fxo_ks
channel => 3
channel => 2

; infohigh fax modem
context=internal
signalling=fxo_ks
echocancel=no
echocancelwhenbridged=no
echotraining=no
threewaycalling=no
channel => 1

; Qworst line
context=incoming
echocancel=yes
echocancelwhenbridged=yes
echotraining=yes
rxgain=10.0
txgain=1.2
signalling=fxs_ks
faxdetect=incoming
channel => 4

Is there something else I need to do? Do I have to turn off echo
cancellation on the outbound line too? I don't think I really want to do
that all the time, or do I? If it only needs to be off when dialing out,
how do I accomplish that?

Thanks for any advice,

--Greg

[kpfleming at digium.com]

Greg Woods wrote:

[adam at plexicomm.net]

I've been able to run low speed modems through a SIP ATA and an IAX
trunk....bridged by asterisk.

I would assume that in this day and age any modem application through
asterisk is probably for either a remote console or some sort of control
system. Either way using SIP and a very low speed should work for that
type of stuff.

[greg at gregandeva.net]

On Tue, 2008-03-04 at 12:05 -0600, Kevin P. Fleming wrote: