It's a signal power thing:  FCC Rules, Part 68 specify:

"In 'universal' configurations, the proper attenuator shall be installed or
adjusted by the telephone company at the time of installation, based upon
the loop loss of the telephone line, to arrive at the optimum power level
of -12dBm at the central office..."

This is a limit imposed upon telephone companies by the FCC in an effort to
limit/eliminate interference.  It effectively limits the speed of any modem
to 53K.

The FCC has proposed to raise this limit to -6dBm, which will allow modem
operation at a full 56K.  Of course, even if this proposal is addopted,
modem speed will still be determined by your individual installation and
limited by line noise, etc.

Dave
------------------------------------
Subject: Re: [PCBUILD] Connection Speed


>Jim-
>I believe it is bandwidth that is limited.
>
>Lee Kenna
>
>                Curious about the people moderating your
>                   messages? Visit our staff web site:
>                     http://nospin.com/pc/staff.html
>

                Curious about the people moderating your
                   messages? Visit our staff web site:
                     http://nospin.com/pc/staff.html