COM1 unavailable (HP true RS-232 )

[rihtt]

I am disappointed .
I bought the HP ProBook laptops thats still to date are delivered with windows 7 professional & a real physical COM port.

I need it for serial-interface communication instead of fooling around with usb-adapters.


But to my surprise,the com port seems to fail on me! And the virtual-usb adapters works better.
Very often the com1 just goes unavailable:


cmd

mode com1

-unavailable for the moment



Also when listing com ports within pshell it appears, but when check mode comX you should se
all of its settings, like baudrate etc :

PS C:\Users\rihtt> [System.IO.Ports.SerialPort]::getportnames()
COM1

When connecting my external usb-adapter it appears as COM10 and works fine. I do believe that it has to do with the so called XP MODE


I Run the virtual XP MODE PC on this windows7, and they share hardware. The com1 is also listed within the virtual machine but it doesnt work.


Is there anything to do at all, or is this hardware issue thats the manufactor H P should do?

 

[fireberd]

If it works OK in Windows 7 (shows as working in the Device Manager) but not in XP Mode, I would suspect an issue with XP mode and not a hardware or HP problem.

 

[rihtt]

I am afraid its not that simple.


1 ) The COM1 port shows up in the devmanager.
status "working"

as administrator I could also change its number, and the properties like baudrate.


But my applications both in windows7 (host) & XP Mode (virtual guest) finds the COM1.
But they CANT USE IT.

And when accessing it from cmd - mode com1 = its unavailable.


I can not update the driver with windows update,it tells me its already is the latest.

And the manufactor (HP) diagnostic, utilitys etc dont do shit.

 

[Megahertz07]

COM ports used to be very sensitive to IRQ. What IRQ is your COM using? Is it sharing it with another device?

 

[rihtt]

COM ports used to be very sensitive to IRQ. What IRQ is your COM using? Is it sharing it with another device?

Look, Maybe its something about windows 7 afterall...

win 7 pro (host) cmd to the right tells the port is unavailable

xp mode (guest) cmd inside virtual machine find port + properties






Conclusion:

The Win 7 (host) cant find the local serial port. i.e port unavailable
No matter if the virtual machine is running or not.




According to Windows7 (COM port 1 properties)

COM1  
extended IO  Bus

driver info - two files used -

C:\WINDOWS\system32\drivers\serenum.sys
as shown above.






But take a look at the second file (driver)

C:\WINDOWS\system32\drivers\serial.sys


this is wierd, how could a Brother file end up here? Most be something wrong, presumbly when installing a brother printer? When listing devices there is no such printer pointing to serial port. Then I thought if LPT1 or some other printer could do irq-conflict.

LPT 1
RESOURCE
 I/O     0378-037F
IRQ  0778-077A

COM 1
RESOURCE
 I/O    03F8-03FF
IRQ  0x00000004 (04)

 

[Megahertz07]

On Win 7, launch system Information (%windir%\system32\msinfo32.exe) and look IRQ under Hardware resources. Is the Com1 IRQ shared with another device? Open device manager and uninstall com1 drivers and reboot. My MB also has a com port that is disabled on BIOS. I'll enable it and see what drives it install under Win 7 and I will return to report.

 

[rihtt]

Solved

On Win 7, launch system Information (%windir%\system32\msinfo32.exe) and look IRQ under Hardware resources. Is the Com1 IRQ shared with another device? Open device manager and uninstall com1 drivers and reboot. My MB also has a com port that is disabled on BIOS. I'll enable it and see what drives it install under Win 7 and I will return to report.

Solved. Just before your post

There was some conflict with a printer (!)

I logged in as administrator.
I checked all printers and their port-settings.
somehow 2 inactive printers was configured to port com1.
but none had brother driver (its still there as \serial.sys)

One of them had unfinished print jobs.
Que of documents.

So I canceled it all.
Then Restarting.
Then Uninstalling printers
Then Rebooting again


Now the COM 1 port works fine. Both from Windows7 applications and XP Mode.





I guess checking the IRQ-channel as you mentioned would find the same problem,
But I Couldnt obviously. I Failed to read out the msinfo32 anyway!

Because when reading the list of compontents , it only says the COM1 was OK and channel IRQ 4.



PS.
I hit
win - r
msinfo32
enter

 

[Megahertz07]

This is my MB Com1. I think it is built in the Z170 chipset

 

[Megahertz07]

Good news!!! I've told you on my fist post to see if IRQ was shared with other device.