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

[Rich Adamson]

> > > 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.

At the T1 Smartjack point, the level setting is for the T1 digital signal,
not the audio level. The two have nothing to do with each other.
 
> Does this make sense to anyone?  Wouldn't the -10db affect the *digital* levels, not the analog
> waveform encoded within the digital signal?

Correct.
 
> 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.

That last statement indicates their level of knowledge; almost zero.

A milliwatt generator creates an audio signal at 1,004 hz and 0db. It
has nothing at all to do with a T1 signalling, etc. You can yell into
a analog telephone set and create audio levels greater then 0 db.

Whoever is feeding you the above words apparently has no knowledge of
telephony whatsoever.