GPOs and COM/LPT ports

[robert.yung]

Hi,

I am having issues with running certain legacy applications that
require communication with parallel port dongles and COM port
instruments on an XP workstation. Logging on with admin does not fix
the problem so I'm fairly certain that rights are not an issue. In
some cases, the dongles are not detected by the software at all, in
others, software will detect a device on a COM port, but not transfer
any information to it.

To top it off, the affected software works fine on another XP machine,
at the same patch level, that is *NOT* on the domain. This leads me
to wonder if its a GPO thing?

Clues? Suggestions? Any help would be appreciated..

Thanks alot!

 

[Guest]

I was led to believe that since Windows NT, application programs can only
communicate with ports via the Windows file API.

Detection of static bit-patterns on a 'dongle' normally requires a .DLL
which is registered as a 'Trusted Driver' . I would check to see if the
machine which works has such a .DLL, but it would help to know the name on
the needle before searching the haystack!

 

[robert.yung]

Hi..thanks for the reply. There is unfortunately no driver that I can
see beyond the default COM/LPT driver that comes with XP. For another
application, there IS a driver, how do I check to see if its trusted?
Also if its not, what can I do to force XP to use it?

Thanks again.

 

[Steven L Umbach]

There is one setting I can think of to check and that is in Local Security
policy under local policies/security options - devices:unsigned driver
behavior. If it is set to do not allow installation that could be an issue.

Steve

 

[Guest]

Sorry, you have reached my competence limit in this area!
Hope Steven's post may be a pointer.