[asterisk-users] fxotune vs rxgain/txgain

[Noah Miller]

Hi Matthew -

> These techniques are not mutually exclusive, I usually want people to
> use gain modification as the last step in trying to eliminate echo
> (after balancing the hybrid and making sure you are using a good echo
> canceller).
>
> In the case of running fxotune, your zapata.conf software gain levels
> should not affect its operation.  If you are using any of the hardware
> gain settings (wctdm24xxp module parameters) you should normalize those
> to 0 beforehand so that they do not interfere with the calibration process.

Thanks for your responses!

I actually didn't realize there are hardware gain settings available
for wctdm24xxp (is there any documentation on this?  I can't seem to
find any).  I assume the hardware gains default to 0 if left unset?

Just two more questions:
1) I think we were experiencing ECFO with an rxgain setting of +10db
(after having balanced the hybrid using fxotune).  I'm guessing this
is because that rxgain value amplifies the echo a bit too much.  I
know this is a bit of a loaded question, but is there a certain range
of values for rxgain/txgain that we should stay within in order to
avoid exacerbating any echo issues?
2) Are rxgain/txgain values applied before or after hardware echo cancellation?


Thanks,
Noah