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Skriven 2008-09-08 01:16:38 av FidoNews Robot (2:2/2.0)
Ärende: FidoNews 25:36 [02/04]: General Articles
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                        GENERAL ARTICLES
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             Is there a future for POTS?
         By Michiel van der Vlist, 2:280/5555


The first electric telephone was constructed in 1861 by Philipp Reiss
of Germany. It covered only a very short distance (within the same
building) but it was the start of the world encompassing telephone
network as we now know it.

At first the telephone network was used for voice only, but as
technology evolved it was used for other things as well. Newspapers
send pictures from one place to another. Later remote computer
terminals were connected to mainframes over telephone lines. These
techniques were all based on converting the signals into something
that for the telephone network was close enough to a voice signal to
transmit it through the system. A typical telephone network will
transmit analog signals in the range 300 - 3500 Hz. The equipment that
converts the signal is called a modem. An Acronym for MOdulater -
DEModulator.

When it started out around 1985 FidoNet was based on modems over
analog telephone lines. Modem technology evolved to increase the speed
from 300 bps in 1985 to 56 kpbs around 1998. After that modem
evolution stopped because other technologies that replaced data
transport over classic analog telephone lines became widely available
for, and affordable to the general public.

So far for the history.

Today most of the volume of data transported through Fidonet is done
via TCP/IP over dsl or cable. Some nodes still use modem connections
over POTS as their only means of connection and a few use more exotic
means to connect. Although the number of bits transported over POTS
has fallen sharply over the last decade, the number of systems -
nodes, points and users - that have it as their only means of
connection is still significant.

On the other hand, a growing number of FidoNet participants have done
away with their POTS lines and use TCP/IP over dsl or cable as their
only means of connection. So called ION's (InterNet Only Nodes) are
now very common even at the host and RC level. The question has arisen
whether FidoNet as a whole should continue to support POTS. Some would
not mind to see it go entirely and some say we should maintain support
for POTS as long as there is one single system that depends on it.

The reality is that it may be out of our hands.

VOIP (Voice Over IP) has become increasingly popular as a replacement
for classic analog telephony. There is an increasing number of people
who cancelled their POTS connection and use VOIP telephony
exclusively. The technology has evolved to the point that quality of
VOIP need no longer be inferior to classic analog telephony. For the
human ear that is. For data VOIP is less suitable. Modem over VOIP may
result in a usable connection, but ever so often it does not or the
speed is reduced to 9k6 bps or less. The reason is that VOIP uses
lossy compression and the signal is broken up into packets that may or
may not arrive with exactly the same temporal separation as they are
send. (Packet jitter). It is hardly noticeable by the human ear, but
packet jitter is devastating for modem signals.

So if you want reliable fast modem connections, a POTS line is needed.
The problem is that not only are the end users switching to VOIP, here
in Western Europe the telcos themselves are taking down their POTS
systems in favour of VOIP. KPN, the leading telco and keeper of the
infrastructure in The Netherlands has announced that the classic POTS
network will be shut down by 2010 and from then on the network will be
VOIP only. In Belgium and Germany the major telcos have made similar
announcements. NGN, Next Generation Network, they call it. My personal
estimate is that the 2010 deadline is not realistic and will be
extended, but there is no doubt that classic POTS as we know it will
come to an end in the near future. This will have little or no effect
for my old mother who only uses the telephone for voice conversations,
but for FidoNet it may mean that, like it or not, we will have to tell
the sysops of the remaining POTS only systems that they will either
have to upgrade to Fido over IP or say goodbye. We may want to
maintain support for POTS but if the infrastructure no longer supports
it, then that is it.

I do not expect VOIP technology to improve to the point that it will
reliably transport modem signals. The telcos have no vested interest
in it. On the contrary they want to make money on dsl and cable. And
since they never officially offered anything but voice quality over
voice lines, anyone making legal claims will have no leg to stand on.

It looks like that within the next couple of years FidoNet wil no
longer be able to use POTS in large parts of the world. Don't make the
mistake of thinking this will be limited to Western Europe. The Telcos
in other parts of the world will soon follow if they see how much they
can save by dumping classic POTS technololy and replacing it with
VOIP.

The future of POTS? POTS has no future, it will soon be history. We'd
better prepare for the situation that within five years Fidonet will
for all intents and purposes be IP only. Like it or not.


Michiel van der Vlist
2:280/5555


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