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Full Discussion: Serial Lines Explained
Top Forums UNIX for Dummies Questions & Answers Serial Lines Explained Post 302912179 by edfair on Wednesday 6th of August 2014 11:32:31 AM
Old 08-06-2014
Since most serial communications is via a UART this might help with the data transfer part:
Universal asynchronous receiver/transmitter - Wikipedia, the free encyclopedia

The UART voltage swings are between 0 and 5 volts. This signal is inverted and expanded to higher voltages by line drivers for transmission and inverted again and reduced to 0/5 swings by line receivers on the receiving end.

The transmitted signal starts degrading immediately and at higher transmission speeds it can be expected to be useless beyond 50 feet due to RC effects. (with a scope you would see rounding of what started as sharp shapes of voltage transitions)
 

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WWW::Wikipedia(3pm)					User Contributed Perl Documentation				       WWW::Wikipedia(3pm)

NAME
WWW::Wikipedia - Automated interface to the Wikipedia SYNOPSIS
use WWW::Wikipedia; my $wiki = WWW::Wikipedia->new(); ## search for 'perl' my $result = $wiki->search( 'perl' ); ## if the entry has some text print it out if ( $result->text() ) { print $result->text(); } ## list any related items we can look up print join( " ", $result->related() ); DESCRIPTION
WWW::Wikipedia provides an automated interface to the Wikipedia <http://www.wikipedia.org>, which is a free, collaborative, online encyclopedia. This module allows you to search for a topic and return the resulting entry. It also gives you access to related topics which are also available via the Wikipedia for that entry. INSTALLATION
To install this module type the following: perl Makefile.PL make make test make install METHODS
new() The constructor. You can pass it a two letter language code, or nothing to let it default to 'en'. ## Default: English my $wiki = WWW::Wikipedia->new(); ## use the French wiki instead my $wiki = WWW::Wikipedia->new( language => 'fr' ); WWW::Wikipedia is a subclass of LWP::UserAgent. If you would like to have more control over the user agent (control timeouts, proxies ...) you have full access. ## set HTTP request timeout my $wiki = WWW::Wikipedia->new(); $wiki->timeout( 2 ); You can turn off the following of wikipedia redirect directives by passing a false value to "follow_redirects". language() This allows you to get and set the language you want to use. Two letter language codes should be used. The default is 'en'. my $wiki = WWW::Wikipedia->new( language => 'es' ); # Later on... $wiki->language( 'fr' ); follow_redirects() By default, wikipeda redirect directives are followed. Set this to false to turn that off. search() Which performs the search and returns a WWW::Wikipedia::Entry object which you can query further. See WWW::Wikipedia::Entry docs for more info. $entry = $wiki->search( 'Perl' ); print $entry->text(); If there's a problem connecting to Wikipedia, "undef" will be returned and the error message will be stored in "error()". random() This method fetches a random wikipedia page. error() This is a generic error accessor/mutator. You can retrieve any searching error messages here. TODO
o Clean up results. Strip HTML. o Watch the development of Special:Export XML formatting, eg: http://en.wikipedia.org/wiki/Special:Export/perl SEE ALSO
o LWP::UserAgent AUTHORS
Ed Summers <ehs@pobox.com> Brian Cassidy <bricas@cpan.org> COPYRIGHT AND LICENSE
Copyright 2003-2011 by Ed Summers This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself. perl v5.10.1 2011-04-05 WWW::Wikipedia(3pm)
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