42 lines
1.3 KiB
HTML
42 lines
1.3 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="SGML-Tools 1.0.9">
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<TITLE>Keyboard scancodes: Special keyboards - AT keyboards</TITLE>
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<LINK HREF="scancodes-5.html" REL=next>
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<LINK HREF="scancodes-3.html" REL=previous>
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<LINK HREF="scancodes.html#toc4" REL=contents>
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</HEAD>
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<BODY>
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<A HREF="scancodes-5.html">Next</A>
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<A HREF="scancodes-3.html">Previous</A>
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<A HREF="scancodes.html#toc4">Contents</A>
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<HR>
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<H2><A NAME="s4">4. Special keyboards - AT keyboards</A></H2>
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<P><I>The AT keyboard adds a keyboard controller.
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The numeric keypad is now separated from the main keyboard.
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There is a single new key, with scancode 84 = <B>54</B>,
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namely SysRq.</I>
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<P>The protocol for AT and later keyboards differs from that for
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XT keyboards. Some old keyboards have an XT/AT switch on the
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backside that selects the appropriate protocol.
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Other keyboard autodetect XT or AT mode.
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<P>
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<FIGURE>
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<EPS FILE="absent">
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<IMG SRC="xt-at-switch.jpg">
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</FIGURE>
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<P>
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<P>The KeyTronic KB101-1 keyboard has four switches of which the first two
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indicate the desired behaviour (00 - autodetect, 01 - unused,
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10 - PC/XT, 11 - AT). Autodetect does not always work.
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<P>
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<P>
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<HR>
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<A HREF="scancodes-5.html">Next</A>
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<A HREF="scancodes-3.html">Previous</A>
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<A HREF="scancodes.html#toc4">Contents</A>
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</BODY>
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</HTML>
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