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Re: [LUG] Asterisk - quiet caller on POTS line

 

On Thu, 4 Jul 2013, Mark Evans wrote:

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On 04/07/13 11:30, Rob Beard wrote:
Hi folks,

I'm having a few issues with Asterisk and I wondered if someone
might be able to suggest any ideas how I might be able to solve
it?

Basically we've got a machine running Asterisk with a Digium
analogue card with two FXO ports and two FXS ports.  The phones we
use are Grandstream GXP1400/GXP1405 phones and one little
Grandstream DECT IP phone (can't remember the model number off the
top of my head).
Maybe a DP715
Not really relevant here though.

I've tried adjusting the txgain in chan_dahdi.conf and it doesn't
seem to make much if any difference (I've also restarted dahdi and
Asterisk after making the changes).  It's currently set at txgain =
22.0 (I wasn't sure how high to put it to).
You could try a Zycoo ZX20-A202. Which is an ARM based Asterisk box with
two FXO ports built in. (Around £140).
They all use the same modules - or the same reference design for the 
analog side of things. The issue here is that the incoming line is long, 
so the voice volume is low - the hardware can amplify it a bit, but not by 
much.
How long an extension cable? Might be better to run CW1308, even CAT5, t
a secondary socket. Keeping the flex to under 2m.
A few meters of bell wire won't make any difference to a few miles of 
copper already there, as far as the audio is concerned.
I've been there many times. Sometimes I can tweak the gains and make it 
better, sometimes not. If the internet line is stable (on another copper 
pair) then I just port the numbers into my platform and be done with it.
Try swapping the modules over on the TDM card, or I have a box of spares 
if you want to try some others. (OpenVox)
Gordon
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