Very Computer

I believe there was someone else on one of these groups
having hastle - I haven't seen the post - if someone
sees it can someone pass me a copy.

Symptoms:
Serial port 2 (25 way) doing nothing.

Fix:
The motherboard has two lots of 10way DIL IDC headers,
one for each serial port.  The pin outs on these correspond
to the pin out of a 9 way AT style serial port.  The  lead
I had going from the 25 way socket on the back of my machine
to the IDC headers was wired in the wrong order for these
connectors on the motherboard.  In the end I replaced this
lead by another 9 pin one.

M*of the story:
The 25way socket -> 10 pin IDC cables you get on I/O cards
probably won't work on all boards, on both channels and not on motherboards.

Easy test:
Try unplugging the lead from the board going to the 1st serial
port and plugging it into the 2nd serial port and try your
mouse on that.

--
-------------------------------------------------------------------------------

------------ (University of Manchester - AMULET Group) ------------------------

Quote:>Hi All,
>I've just fixed the 2nd serial port on my Plato Baby AT
>Pentium system.
>Fix:
>The motherboard has two lots of 10way DIL IDC headers,
>one for each serial port.  The pin outs on these correspond
>to the pin out of a 9 way AT style serial port.  The  lead
>I had going from the 25 way socket on the back of my machine
>to the IDC headers was wired in the wrong order for these
>connectors on the motherboard.  In the end I replaced this
>lead by another 9 pin one.
>M*of the story:
>The 25way socket -> 10 pin IDC cables you get on I/O cards
>probably won't work on all boards, on both channels and not on motherboards.

            1       2       3       4       5

                6       7       8       9

Others wire it like this:

            1       2       3       4       5

                9       8       7       6

Which way is correct depends on how the IDC header pinouts are arranged.
Intel's motherboards use the first pinout, which actually corresponds to the
numbers on the D-shell pins (look inside the shell, you will see little
numbers stamped next to each pin).  Obviously, a header cable made for one
will not work on the other.  The same sort of reversal happens with the 25
pin D shells, too.  I've seen I/O boards with the 9-pin headers wired right,
and the 25 pin headers wired backwards.  And vice versa.  And inverse vice
versa (verce visa?).
--

"The avalanche has already begun.  It is too late for the pebbles to vote."