<br><font size=2><tt>asterisk-users-bounces@lists.digium.com wrote on 10/16/2005
07:49:38 AM:<br>
<br>
> Here's a couple of ways to determine levels...<br>
> <br>
> 1. using the model 4 transmission test set, attach the tone generator<br>
> to one analog pstn line and the transmission level test jacks to a<br>
> second pstn line. Dial from one line to other and measure the tone.<br>
> Divide by two, and the result is the loss associated with a single<br>
> analog pstn line from your location to your central office.</tt></font>
<br>
<br><font size=2><tt>Remember, I'm not working with simple POTS lines.
I've got an Adtran TA 612 providing CO lines from a T1. There
is nothing that says that the RX and TX settings on the Adtran are the
same... Therefore, just dividing by 2 won't work.</tt></font>
<br>
<br><font size=2><tt>Also, couldn't there be an issue on standard POTS
lines where the effect upon a singnal between TX and RX is different?</tt></font>
<br>
<br><font size=2><tt>It seems you're just exchanging one set of assumptions
for another. But you're the expert! :)</tt></font>
<br>
<br><font size=2><tt>> 2. use one of those analog pstn lines to dial
the distant milliwatt<br>
> generator (regardless of where its located), and measure the level<br>
> of the tone. Subtract the loss determined from step #1 and now
you<br>
> have the loss associated with facilities interconnecting your central<br>
> office all the way to the distant milliwatt generator.</tt></font>
<br>
<br><font size=2><tt>This doesn't address the problem above, correct?</tt></font>
<br><font size=2><tt><br>
> The end result will be whatever loss values you measure/calculate,<br>
> you'll still have to play around with the rxgain & txgain to <br>
> minimize the echo while also maximizing the audio levels. The<br>
> process will become a _qualitative_ eval process, not a quantitative<br>
> one. It doesn't make any real difference which tools you use to get
<br>
> there or exactly where the milliwatt generator happens to reside.</tt></font>
<br>
<br><font size=2><tt>So how important or valuable will getting a milliwatt
test number be?</tt></font>
<br><font size=2><tt><br>
Tim Massey</tt></font>
<br>