Cannot Access Or Open RS-232 Serial Port


Robert Cochran

Hi, I am trying to connect a Texas Instruments TI-89
graphing calculator to a computer running Windows XP
Pofessional. The connection is being made by a TI Graph-
Link grey cable between the calculator and the comptuer's
9-pin RS232 serial port. I followed TI's instructions and
first installed their "Ticonnect" software (version When I run the software, it cannot detect the
calculator. The software opens a dialog box inviting me to
pick connection parameters and one of these is a list of
COM ports. It shows COM1 and COM3. It is unable to detect
the calculator on either port.

I also installed separate TI Graph-Link software which
issues an immediate error message when launched; the
message is either "cannot open COM port." or "cannot open
serial port.", I forgot to write down the exact message.

The computer itself is an Emachines eMonster 600id with a
PS/2 mouse and a single RS-232, 9-pin serial port. Even
though it has a broadband connection now, the original PCI
modem is still installed and that seems to be taking COM3
according to Control Panel/Modems.

This problem seems very similar to one that a friend of
mine had with Windows NT 4. She couldn't hot sync her
serial-cable connected Palm because the COM port was
listed as busy. Apparently, changing settings in
Accessibility Options (Control Panel) enabled her to hot
sync successfully. But when I look at Accessibility
Options in Windows XP, it doesn't seem like anything
is "turned on"? Or maybe I am mistaken?

I have 3 questions to ask:

How can I find out which device and/or which program is
holding COM1 open?

How can I regain the use of the physical serial port so
that the Ticonnect software can detect the calculator via
the cable?

Will buying an additional serial port (in the form of a
hardware PCI card) be any help in this situation? The
particular eMachines is extremely limited with only 3 PCI
slots, 256M of memory, and a small power supply.

Thanks a lot

Robert Cochran


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