Windows 7 Forums

Welcome to Windows 7 Forums. Our forum is dedicated to helping you find support and solutions for any problems regarding your Windows 7 PC be it Dell, HP, Acer, Asus or a custom build. We also provide an extensive Windows 7 tutorial section that covers a wide range of tips and tricks.


Windows 7: COM1 unavailable (HP true RS-232 )

18 Aug 2016   #1
rihtt

windows 7 Professional x64
 
 
COM1 unavailable (HP true RS-232 )

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
Code:
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 :


Code:
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?


My System SpecsSystem Spec
.
18 Aug 2016   #2
fireberd

Windows 10 64 bit
 
 

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.
My System SpecsSystem Spec
19 Aug 2016   #3
rihtt

windows 7 Professional x64
 
 

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.
My System SpecsSystem Spec
.

19 Aug 2016   #4
Megahertz07

Windows 7 HP
 
 

COM ports used to be very sensitive to IRQ. What IRQ is your COM using? Is it sharing it with another device?
My System SpecsSystem Spec
22 Aug 2016   #5
rihtt

windows 7 Professional x64
 
 

Quote   Quote: Originally Posted by Megahertz07 View Post
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)

Code:
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.



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


Code:
COM 1
RESOURCE
 I/O    03F8-03FF
IRQ  0x00000004 (04)
My System SpecsSystem Spec
22 Aug 2016   #6
Megahertz07

Windows 7 HP
 
 

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.
My System SpecsSystem Spec
22 Aug 2016   #7
rihtt

windows 7 Professional x64
 
 
Solved

Quote   Quote: Originally Posted by Megahertz07 View Post
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
My System SpecsSystem Spec
22 Aug 2016   #8
Megahertz07

Windows 7 HP
 
 

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


Attached Thumbnails
COM1  unavailable  (HP true RS-232 )-com_general.jpg   COM1  unavailable  (HP true RS-232 )-com_resources.jpg  
Attached Images
COM1  unavailable  (HP true RS-232 )-com_driver.jpg 
My System SpecsSystem Spec
22 Aug 2016   #9
Megahertz07

Windows 7 HP
 
 

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

 COM1 unavailable (HP true RS-232 )




Thread Tools Search this Thread
Search this Thread:

Advanced Search




Similar help and support threads
Thread Forum
Com1 in Ports vs. Com1 in Modems
Hi, My current challenge is to get a 56K modem working in my new (bought used) desktop running Windows 7. My question is: Is the Com1 referred to in "Ports" in Device Manager the same Com1 that is referred to in "Modems" in Device Manager? Should I have Uninstalled and Reinstalled Com1 in...
Hardware & Devices
How can I get rid of the yellow exclamation mark against Com1
I've tried cleaning the registry, uninstalling and reinstalling the port then rebooting but it's still there. Looking around the net there appears to be software that claims to be able to fix it but none of it is from MS. So I'm scared to use it. Also tried the MS Mrfixit but it couldnt. Does...
Drivers
Using COM1 over local network
Hi ! I have a POS application.I'm using one thermal printer connected to COM1,I create a bat file wit this command : copy mydata.txt COM1: I run this bat and printer is working fine. I've installed my application on a second computer in the network and I need to print from there to the...
Network & Sharing
True Image 2011 vs True Image 2010
I'm wondering exactly what improvements and changes have been made that might make it worthwhile to upgrade. I don't much care about cosmetic changes, only in those that actually make the program work better. I took a look at the Acronis website, but didn't find a change log, only literature to...
Software
COM1 port once available for Visor Prism is now not ...
Hi! My Handspring Prism was working fine with my Win 7 until recently. Now, every time I try to sync it, I get a "The selected port, COM1, is not available at this time. Hotsync manager will open the port when it becomes available." My Device Manager won't tell me what is using COM1 and says...
Hardware & Devices
USB to COM1
Hi is there any app to use a usb device on a COM1 port? i know i can make a cable but i need a software? if theres any out there, im searching and nothing. Thanks
General Discussion


Our Sites

Site Links

About Us

Find Us

Windows 7 Forums is an independent web site and has not been authorized, sponsored, or otherwise approved by Microsoft Corporation. "Windows 7" and related materials are trademarks of Microsoft Corp.

Designer Media Ltd

All times are GMT -5. The time now is 07:47.

Twitter Facebook Google+



Windows 7 Forums

Seven Forums Android App Seven Forums IOS App