[asterisk-users] fxotune vs rxgain/txgain

[Noah Miller]

Hi All -

I hope somebody can clarify for me what exactly fxotune does, and how
it is related to gain settings.  I've been reading what appears to be
conflicting information from various sources.

I've got a box with an AEX800 with 6 lines (from Qwest) running
asterisk and zaptel versions 1.4.20.1 and 1.4.11 respectively.  We've
been experiencing some echo/quality issues on certain calls which seem
to happen on all 6 of the lines.  I manually calibrated the
rxgain/txgain using ztmonitor and a milliwatt test line to the
somewhat improbable levels of +10.0/-2.0 (about the same for all 6
lines).  These settings yield acceptable call volumes, but echo and
noise are problems.

If I run fxotune, it gives me the following numbers:

1=10,0,0,0,0,0,0,0,0
2=12,0,0,0,0,0,0,0,0
3=12,0,0,0,0,0,0,0,0
4=10,0,0,0,0,0,0,0,0
5=10,0,0,0,0,0,0,0,0
6=10,0,0,0,0,0,0,0,0

Two questions here:

1) What do these numbers mean?  Are they in any way related to either
rxgain or txgain?
2) Am I supposed to set rxgain and txgain back to 0 if I use fxotune -s?

If I do use these fxotune settings and set rxgain and txgain to zero,
the volume on incoming zap calls is almost too low to be heard, but
echo issues seem to be solved.

Do I have to choose between 1) acceptable call volume with echo or 2)
super-quiet call volume without echo?  Should I petition Qwest to
install a repeater?


Thanks,
Noah