Re: AOL, 288 to 336

Jay Shoup (jashoup@indiana.edu)
Mon, 15 Apr 1996 18:36:53 +5000


Yes it actually does apply to telephone lines. All calls, voice or
data require bandwidth, a phoneline has a predetermined bandwidth. The
only way to get more data down a line with a predefined bandwidth is
to provide some form of compression. This is just what high speed
modems do. (Don't be mislead, compression can come in many forms, data
compression such as V42, software, is one such form. Compression can
also come in the form of hardware modulation schemes such as V32Bis
and V34, modulation techniques, are also forms of compression)

Actually, no not every phone line can do 28.8. Again I repeat, to do
28.8 a phone line must meet certain parameters, noise, harmonic and
phase distortion, etc. must meet certain specs.

A loop (Often called a local or subscriber loop) is the pair of wires
that run from your home to the telephone switching system. When you
connect to another party, the phone company combines your subscriber
loop to the other parties subscriber loop. The term loop actually
comes from the fact that the two wires leaving your home are connected
in the telco-office via to one another to form a complete circuit.
(techno mombo jumbo)...

Loop length has very little to do with the ability to do 28.8, see
above. (except that long lines are more susceptible to noise, echo
etc.)

>
> But I don't think this applies to conventional phone calls, does it?
> Every phone line can do 28.8, theoretically, as long as the loop
> isn't to long? what is a loop anyway, how does it work?
>

Jay!
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Jay Shoup
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Indiana University
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