[asterisk-users] TDM analog cards, volume, echo, fxotune, ztmonitor and HPEC

[Matthew Fredrickson]

What version of zaptel are you using fxotune from?  You should be using  
1.4 fxotune, between 1.2 and 1.4 there was a pretty significant rewrite  
that will probably give you more improvement.  Also, just in case you  
hadn't, make sure you're doing an fxotune -s on bootup so that it  
applies your fxotune configs to your cards each time you boot.

Matthew Fredrickson

On Mar 25, 2007, at 2:21 PM, Stephen Bosch wrote:

>
> Hi:
>
> Tzafrir Cohen wrote:
>> Just a partial answer:
>>
>> On Sat, Mar 24, 2007 at 10:24:18AM -0600, Stephen Bosch wrote:
>>> Hi, everyone:
> <snip>
>>> Now, standard analog sets have a varistor circuit to compensate for
>>> these variations in signal level, but it would appear that the TDM  
>>> cards
>>> don't incorporate this kind of dynamic gain control.
>>>
>>> Zaptel allows you to control the transmit and receive gain at the
>>> interface card, but isn't that what fxotune is supposed to do? Tune
>>> those gains so that the echo is minimized? I don't want to play with
>>> gain only to undo the echo tuning done by fxotune.
>>
>> No, this is not Zaptel. This is Asterisk's chan_zap (Asterisk zaptel
>> channel).
>
> Gain can be *set* in zapata.conf -- but aren't those adjustments made  
> at
> the driver level?
>
>> fxotune, however, runs directly with zaptel. Thus it cannot be  
>> affected
>> by whatever gain settings you have in zapata.conf.
>
> Doesn't fxotune make gain adjustments? If gain adjustments are part of
> the echo optimization process, then wouldn't changing the gain levels  
> in
> zapata.conf impact echo and undo part of what fxotune has set?
>
>>> Similarly with ztmonitor: Is tinkering with the gain using ztmonitor
>>> going to undo the tuning done by fxotune, or can I do both?
>>
>> tinkering with the gain with ztmonitor?
>
> Well, using ztmonitor to measure signal levels and adjusting gain
> accordingly. The directions for this process may be found at
>
> http://lists.digium.com/pipermail/asterisk-users/2004-November/ 
> 064312.html
>
> Now, this post is more than two years old, and I think it precedes the
> changes made to fxotune; I don't know of many people using it to deal
> with echo -- but my echo is okay, I need to adjust the gain now.
>
> (There's another post dealing with gain and ztmonitor here:
>
> http://lists.digium.com/pipermail/asterisk-users/2005-March/089437.html
>
> )
>
> -Stephen-
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