re: [WriteLog] Keying problem

[Don Hatlestad]

>I am using COM2 for keying.
>I have a problem in that every now and again (say every minute or so
>but not at regular intervals) the PC goes and does something which
>causes the CW sending to be chopped up.

It is possible to improve the performance of Windows XP a little.
I have implemented these changes to my radio computer with success. 
My radio computer is a Dell Lattitude C600 in a docking station. 
The OS is Windows XP Pro SP2.

Disclaimer: these changes that I am describing can screw up
your computer so that it will not work or work worse than before. 
If you have never edited the registry before, don't start now.

First, a reasonable service to set to manual startup is the 
Indexing Service. You should consider disabling Messenger too. 
Change the way these services start up in the Administrative 
tools/Services control panel. The Indexing service is a prime 
suspect for your problem.

Second, to make it so that your computer considers COM2 a priority. 
Add a dword variable named "IRQ3PriorityControl = 1" to the registry 
key: HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\PriorityControl.
The IRQ3 part of the variable can be changed to any interrupt 
that you choose and I assume that COM2 on your computer uses the 
default IRQ for COM2. I suggest that you pick only one IRQ; 
I don't even know if more than one would work and more seems like 
a really bad idea to me. Reboot after you make the change.

You can figure out which IRQs your devices are using. Open the 
Device Manager. Under the view menu, select Resources by type.
Open up the Interrupt request (IRQ) icon. A list will appear 
with the IRQ number and the device(s) that are using it. The 
IRQ number is the x in the IRQxPriorityControl variable name.

Third, set your Windows sound scheme to no sounds in the Sounds 
and Audio Devices Properties control panel under the Sounds tab. 
You should do this anyway if you use other digital modes through 
the sound card.

Fourth, set the color quality of your video display to 16 bit so 
that your computer only has to move two bytes per pixel instead of
four.

The third and fourth suggestions will only improve the overall 
performance of your computer a little.

Best luck,
Don AC7FA