LDP/LDP/guide/docbook/Linux-Networking/PSTN.xml

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XML

<sect1 id="PSTN">
<title>PSTN</title>
<para>
PSTN (Public Service Telephone Network) is the telephone system that is used
thoughout the U.S. and many other countries. Although never intended for
networking, telephone lines can be used for communications for computers.
</para>
<para>
A modem (modulator/demodulator) is used to interface between a computer and
the telephone system. Modems can convert data into audible tones and back.
The fastest two-way modems currently available support a speed of 33.6 Kbps
(kilobits per second).
</para>
<para>
Current modems advertise speeds up to 56 Kbps per second. These modems rely
on digital equipment being used in the phone company's central office and in
the facility (such as the Internet Service Provider) you are dialling into.
The 56 Kbps speed also works in only one direction; the other direction supports
33.6 Kbps.
</para>
</sect1>