Serial ports

[John J. Hughes II]

I have a application which opens the port using .NET 2 serial port handler.
On my computer using WinXP Pro SP2 updated I have three accounts. On two
of the accounts the program is able to open COM1 correctly but on the third
account it says the access is denied, I can open other serial ports. I have
also tried an older application I have that uses the more direct API to
access the port. This is driving me nuts...

Anybody aware of how to give myself permission on the third account. I am
set a admin on all three. The only thing I can think of is the third
account was created recently.

Thanks,
John

 

[Michael A. Covington]

I have a application which opens the port using .NET 2 serial port handler.
On my computer using WinXP Pro SP2 updated I have three accounts. On two
of the accounts the program is able to open COM1 correctly but on the third
account it says the access is denied, I can open other serial ports. I
have also tried an older application I have that uses the more direct API
to access the port. This is driving me nuts...

Anybody aware of how to give myself permission on the third account. I am
set a admin on all three. The only thing I can think of is the third
account was created recently.

Just guessing...

When you perform this test, could some process already have COM1 open? I
think Process Explorer (free utility from Microsoft) will tell you for sure.

 

[Michael A. Covington]

I have a application which opens the port using .NET 2 serial port handler.
On my computer using WinXP Pro SP2 updated I have three accounts. On two
of the accounts the program is able to open COM1 correctly but on the third
account it says the access is denied, I can open other serial ports. I
have also tried an older application I have that uses the more direct API
to access the port. This is driving me nuts...

A few possible leads here:

http://www.thescripts.com/forum/thread524785.html

Portmon utility:
http://www.microsoft.com/technet/sysinternals/processesandthreadsutilities.mspx

 

[John J. Hughes II]

Michael,

Thanks for the sugestions, the port monitor utility shows one of the
programs I wrote opening the port when I log onto that account.

But the problem remains since I can't figure out why or how the program is
starting. Windows Task Manager and Process Explorer do not show the
program running and I have tried seaching for the tasks without avail. I
have also checked all the normal ways to start a program and can not find it
mentioned. The Port Monitor program does not show the port being opened
unless I am logged onto that account.

Any suggestions on where to look?

Regards,
John

 

[D. Yates]

John,

If your using XP, try using this utility:
http://www.microsoft.com/technet/sysinternals/utilities/Autoruns.mspx

Dave

 

[John J. Hughes II]

Dave,

Short answer it is fix...

Long answer: Auto Runs did not show the application being started and as I
said task manager and process explorer did not show it running, very odd.

I switched back to the main account where the serial port worked and search
and deleted all instances my application on the system (figured it could not
start that way). I then switch back to the problem account and yes of
course the serial port was still being held open but by another program.
This time it was active sync which I only use via USB. I disabled the COM1
interface, been so long that I forgot on a new account it would be on by
default. After logging on/off the port was not in use.

I think the port monitor program was misreporting what application was
opening the program, not sure where it gets the information from so I can't
address the matter further.

Again thanks for the help,
John