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Date: | Fri, 28 Aug 1998 11:10:24 -0800 |
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On 28 Aug 98 at 10:10, Daniel Leung wrote:
> >I'm going to guess that the MoBo was recently changed and that they
> >left the original cables installed in the case. This same problem has
> >come up numerous times over the last 2-3 months. Each motherboard
> >has it's own unique pinout for the comm connectors on the board.
There are two obvious/sensible ways to map a 9-pin serial connector
to a 10-pin header on the motherboard. The problem is that the 9-pin
connector is numbered:
1 2 3 4 5
6 7 8 9
while a 10-pin header is normally numbered:
1 3 5 7 9
2 4 6 8 10
Some makers map pin 2 to pin 2, and some map it to 3 and map pin 6 to
2.
[I have not seen any case where a maker has mapped the same
signals, from a 25-pin connector, to different pins on the header
than they use for the 9-pin connector.... Thankfully.]
Neither of these is an official standard, and there are of course
several thousand other possibilities, which don't strike *me* as
obvious/sensible, but might happen to solve some design problem with
a specific board.
David G
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