Intel D425KT serial port problem

[hitsware]

I have aquired a new PC with Intel D425KT board.
Running DOS from bootable USB stick.
(I used this same method with previous PC)
I have 2 devices which use the serial port.
(Woofer Tester and Stamp board)
The Stamp board starts out responding OK
UNTIL I do an edit to the program and then
I get 'communications error'
Similar with the Woofer Tester.
It starts up, but then the readings it gives are
screwy and then also gives 'communication error'
Is there something different with mini-itx boards
or ?

[Jan Axelson]

I would start by checking the flow-control settings and voltages.

Jan

[hitsware]

I would start by checking the flow-control settings and voltages.

Thank You. Can you point me to a device (and/or) procedure (program?)
(From Dos or QBasic)
Mike

[Jan Axelson]

You typically set the flow control either on opening the port or with properties/variables. See the documentation for the routines you're using. Both ends of the link should use the same flow control method, if any.

For the voltages, use a voltmeter or oscilloscope. Search on "RS-232" for details about required voltages.

Jan

[hitsware]

You typically set the flow control either on opening the port or with properties/variables. See the documentation for the routines you're using. Both ends of the link should use the same flow control method, if any.

I've ran the diagnostic ' indentify ' in PBasic and it confirms a problem.
In fact it doesn't acknowledge the Stamp.
It seems (perhaps) I'm sending but not recieving.
The question becomes what is it about this new PC that is different
than any I have had before.
I have never had to do any configuration or setup to get either of
these devices to work.
If I do ' mode ' from dos the only thing I get back is the number
of retrys spec.
If I do ' mode mmm,hhhh,hh,hh ' etc, it echoes my input but seems
not to affect the operation.
Is there perhaps a new trend in the way serial ports work or is this
motherboard perhaps faulty ?
The documentation calls the ports "legacy" so I would think it would act
like an older  PC ?

[Jan Axelson]

For every serial-port connection, both ends need to agree on bit rate, parity, stop bits, and flow control method. If you're not using RS-232 drivers (not sure about the Stamp), you need to be sure the logic voltages are compatible. And be sure you connect inputs to outputs. Some connections require a null-modem cable.

Jan

[hitsware]

FWIW :