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Windows serial port errors

If you have problems getting the serial ports working when running the program under Windows then you may have to disable a function in Windows that blocks the serial ports for DOS programs.

The Windows register key that has to be changed is: 'EnablePowerManager <= 0000 00 00 00 00'
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\VxD\VCOMM

Please notice: It's extremely important that you do exactly as explained below, and if you make any mistakes while running the REGEDIT program, you may stop your Windows installations from working.

  • Start Windows, select 'Run' from the start menu
  • In the box that pops up, type in REGEDIT, then press [Enter]
    (This starts the program REGEDIT)
  • Hit F3 (This open a seach box)
  • In the search box, type in EnablePowerManager, then press [Enter]
    Wait while the program searches ... and locates the key.
    (This may take from seconds to several minutes)
  • Double click the field 'EnablePowerManagement'
    (If you don't see the above field 'EnablePowerManagement', hit F3 to
    continue the search)
    In the window that now appears you should see the code 0000 01 00 00 00
    these digits has to be changed to 0000 00 00 00 00
    (DONT make ANY changes if you DONT see the above digits!)
  • Hit OK in order to save, or hit [Esc] in order to cancel without saving
  • Close the 'Registry' Windows
  • Shut down Windows, then restart the computer.

You find more information on this problem in the 'Microsoft Knowledge Base':
Search for 'COM Ports on Computers with ACPI Support', then click on the link for
MS-DOS-Based Programs Unable to Initialize COM Ports on Computers with ACPI Support (Q252184)

For further information refer to www.bailine.com/faq