41 lines
1.4 KiB
HTML
41 lines
1.4 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN">
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<HTML>
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<HEAD>
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<META NAME="GENERATOR" CONTENT="LinuxDoc-Tools 0.9.21">
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<TITLE> Modem-HOWTO: Appendix G: Fax pixels (dots)</TITLE>
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<LINK HREF="Modem-HOWTO-28.html" REL=next>
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<LINK HREF="Modem-HOWTO-26.html" REL=previous>
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<LINK HREF="Modem-HOWTO.html#toc27" REL=contents>
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</HEAD>
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<BODY>
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<A HREF="Modem-HOWTO-28.html">Next</A>
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<A HREF="Modem-HOWTO-26.html">Previous</A>
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<A HREF="Modem-HOWTO.html#toc27">Contents</A>
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<HR>
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<H2><A NAME="s27">27.</A> <A HREF="Modem-HOWTO.html#toc27">Appendix G: Fax pixels (dots)</A></H2>
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<P> Here's some info on the bloated bandwidth required for standard
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fax including the dot density. You can of course send a fax via your
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modem if you dial the real telephone number of the recipient.</P>
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<P>
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<BLOCKQUOTE><CODE>
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<PRE>
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A4 paper: 216mm (horizontal) * 297mm (vertical)
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normal mode 8dots/mm * 3.85dots/mm
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fine mode * 7.7dots/mm
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extra fine mode *15.4dots/mm
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</PRE>
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</CODE></BLOCKQUOTE>
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</P>
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<P>Each dot is either white or black and thus 1 bit. One sheet of A4
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paper using fine mode is (216*8) * (297*7.7) = about 4 million dots.
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With a compression ratio of 8:1 it takes about 50 seconds at 9600bps
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for transmission.</P>
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<HR>
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<A HREF="Modem-HOWTO-28.html">Next</A>
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<A HREF="Modem-HOWTO-26.html">Previous</A>
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<A HREF="Modem-HOWTO.html#toc27">Contents</A>
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