[Asterisk-Users] Calibrating both RX and TX gain?

[tmassey at obscorp.com]

asterisk-users-bounces at lists.digium.com wrote on 10/12/2005 01:23:57 PM:

> On Wed, Oct 12, 2005 at 12:05:32PM -0400, tmassey at obscorp.com wrote:
> > I am in the middle of trying to get a milliwatt test line to calibrate 
the 
> > rxgain properly.  However, this won't help me with the txgain, will 
it? 
> > How can I properly calibrate the txgain?  By ear?  Or is there a more 
> > scientific method?

> I contacted Rhino to see if they had any suggestions, and they were
> able to give me a few.  What finally worked was setting the Asterisk 
gains
> back to 0 for all channels, then adjusting the gains down on the channel 
banks
> themselves for the phone (FXS) interfaces only.  A huge improvement!  My
> current adjustements are the following:

According to the company that installed the channel bank, there is a 0db 
and -10db setting on the smart jack for the T1.  They claim that this was 
most likely set to -10db by the ILEC when the T1 was installed, and that 
would be causing the low audio volume.

Does this make sense to anyone?  Wouldn't the -10db affect the *digital* 
levels, not the analog waveform encoded within the digital signal?

I'm still trying to get a milliwatt test line to calibrate from.  They 
claim that they won't give that out to end users because "it could fry the 
T1 card".  Sigh.

Tim Massey
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