COM1-4 occupied by the system ? Why?

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System is an not very new Dell Dimension 4550, XP pro SP2.

On my desktop there is one physical serial port RS232 avaible.
However, for some reason, windows does kind of reserve also COm2,3 and 4 for
something, for what I have no idea.
I need now to connect one special USB-RS232 adaptor to my USB bus. This is
an insulated optocoupled adaptor, therefore it need to be connected. Drivers
installed etc, but the device is now becomeing COM5. It would wok nice with
no problem when used by something like Hyperthem, but I need to run it with
some legacy software needing COM1 to COM4 only, does not support anythging
higher.

How can I free the COM2-COM4 in windows so my USB adaptor can take 'the next
one free' within the first 4 low COM ports?
And what is in fact capturing those ports?
 
Otto said:
System is an not very new Dell Dimension 4550, XP pro SP2.

On my desktop there is one physical serial port RS232 avaible.
However, for some reason, windows does kind of reserve also COm2,3 and 4 for
something, for what I have no idea.
I need now to connect one special USB-RS232 adaptor to my USB bus. This is
an insulated optocoupled adaptor, therefore it need to be connected. Drivers
installed etc, but the device is now becomeing COM5. It would wok nice with
no problem when used by something like Hyperthem, but I need to run it with
some legacy software needing COM1 to COM4 only, does not support anythging
higher.

How can I free the COM2-COM4 in windows so my USB adaptor can take 'the next
one free' within the first 4 low COM ports?
And what is in fact capturing those ports?
Click to expand...

Dell might have enabled COM1-4 through bios setup. Go into the bios
setup and disable COM1 or SerialPort1. In configuring the USB-RS232
adaptor, it should select COM1 or there should be a way to force it
to COM1.
 
Otto said:
System is an not very new Dell Dimension 4550, XP pro SP2.

On my desktop there is one physical serial port RS232 avaible.
However, for some reason, windows does kind of reserve also COm2,3 and 4 for
something, for what I have no idea.
I need now to connect one special USB-RS232 adaptor to my USB bus. This is
an insulated optocoupled adaptor, therefore it need to be connected. Drivers
installed etc, but the device is now becomeing COM5. It would wok nice with
no problem when used by something like Hyperthem, but I need to run it with
some legacy software needing COM1 to COM4 only, does not support anythging
higher.

How can I free the COM2-COM4 in windows so my USB adaptor can take 'the next
one free' within the first 4 low COM ports?
And what is in fact capturing those ports?
Click to expand...

http://support.microsoft.com/default.aspx?scid=kb;en-us;315539
 
all somehow confusing.
OK the kb315539 is helpful to discover what is on or off in first place.
However com2 is there on, even there is no com2 avaiable. com 1 is ok, but I
need this one as well being present. com3 and 4 are connected to some usb
device which is not connected however, so I assume I can delete this one from
the device manager list?

com5 is the device which I actualy wanted to have on one of the first 4 com,
so if I delete those other usb ports it will be ok?

the com2 seems to be somehow related to acpi, at least in the properties
stands something like that.
in bios, only com1 appears, it can be either on or off, but as I said, I
need this one running too.
 
Otto said:
all somehow confusing.
OK the kb315539 is helpful to discover what is on or off in first place.
However com2 is there on, even there is no com2 avaiable. com 1 is ok, but I
need this one as well being present. com3 and 4 are connected to some usb
device which is not connected however, so I assume I can delete this one from
the device manager list?

com5 is the device which I actualy wanted to have on one of the first 4 com,
so if I delete those other usb ports it will be ok?

the com2 seems to be somehow related to acpi, at least in the properties
stands something like that.
in bios, only com1 appears, it can be either on or off, but as I said, I
need this one running too.
Click to expand...
You can uninstall any devices you are not using that show up in Device
Manager. That should free up the resources they were using. COM1 and
COM2 are the physical (hardware) RS232 ports on the back of the
computer. They use the same resources (interrupts) as COM3 and COM4 so
if 1 and 2 are enabled, you can't use 3 and 4 either because this old
technology can't share interrupts. Unless you have a physical device
plugged into the serial ports, you should disable COM1 and COM2 in BIOS,
which should make COM1-4 available as virtual ports which your USB
device could use.
 
The com1 is physical there, and I need this one to remain opreational. Also
in Bios, only com1 is stated, nothing about com2.
I checked the properties of the com2 and it seems that it is connected
somehow to acpi power management, have no idea what will happen when deleted
in device mgr.
OK those com3 and 4 are somehow assigned to some usb devices, so I assume I
could delete those two and see if the new device will assign as virtual com3
or 4?

On physical com1, there is permanently connected serial device for
programming some tools in the lab.
 
Otto said:
The com1 is physical there, and I need this one to remain opreational. Also
in Bios, only com1 is stated, nothing about com2.
I checked the properties of the com2 and it seems that it is connected
somehow to acpi power management, have no idea what will happen when deleted
in device mgr.
OK those com3 and 4 are somehow assigned to some usb devices, so I assume I
could delete those two and see if the new device will assign as virtual com3
or 4?

On physical com1, there is permanently connected serial device for
programming some tools in the lab.
Click to expand...
As you said in your original post, your computer has only one physical
serial port, which is why COM2 is absent from BIOS. When you say COM2 is
connected to ACPI power management, I assume its properties show
something like ACPI/PNP004/nnnnnnnn. That is a device code and not to do
with power management. If you uninstall it and Windows is still using
the device, it will be reinstalled next time you reboot, but you may be
asked for the drivers. It is usually safe to uninstall devices in Device
Manager so I would try removing everything except your COM1 device,
reboot and then plug in your RS-232 adapter and see if it gets assigned
to one of the required ports. If that happens, it should stick because
Windows reserves COM ports for devices even when they are not present.

If you can't get it to work, another option would be to add more
physical serial ports by plugging an expansion card into a spare PCI slot.
 
When you say COM2 is
Click to expand...
connected to ACPI power management, I assume its properties show
something like ACPI/PNP004/nnnnnnnn.<

yes , exactly, this is why I thought it will be some kind of ACPI power
management device which I have noidea about.

But OK; I will try to delete this one temporary and see what will happen
then. If I get any of the first 4 free , all will be OK.
 
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