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From: lstowell@pyrnova.pyramid.com (Lon Stowell)
Newsgroups: comp.dcom.modems
Subject: Re: "Loud Carrier"?!? (was Re: Telebit vs. Intel)
Message-ID: <156995@pyramid.pyramid.com>
Date: 28 May 91 21:57:15 GMT
Sender: daemon@pyramid.pyramid.com
Reply-To: lstowell@pyrnova.pyramid.com (Lon Stowell)
Organization: Pyramid Technology Corp., Mountain View, CA
Lines: 35

In article <1991May26.044327.5598@clark.edu> steve@pro-hindugods.cts.com (Steve Fenwick) writes:
>In-Reply-To: message from gandrews@netcom.COM
>
>What _is the advantage of a louder carrier?
   
   On a PSTN line it will improve your social life...gets you
   all sorts of letters, phone calls etc.   (This is true for
   the Permissive type of line which is engineered for a -9dBm
   xmit level...)

   There are other switched lines, such as RJ45 programmed data
   jacks which use a programming resistor to set your xmit
   level.

   The xmit energy of modems is limited in the PUBLIC switched
   network to avoid crosstalk and interference with OTHER voice
   and data users.   The levels were established in
   antiquity...and may be excessively conservative for modern
   lines and gear.

   It is illegal to xmit at higher than the limits set by the
   governments and the telco's.....but the limit is measured in
   a somewhat strange manner.   Exceeding the limit is possible,
   but if you are caught, and the violation is willful, the
   penalties are pretty severe.  If this is done willfully by a
   manufacturer, they could lose their FCC or other PTT
   certification...a pretty nasty penalty.  

   Possibly the "louder" carrier is just a predistortion of the
   xmit spectrum to compensate for roll-off in the network...or
   it even could be a higher energy signal suitable for leased
   lines OR totally private switched networks.  I would find it
   hard to believe a manufacturer would be stupid enough to
   advertise a feature which actually would violate the mandated
   limits...