Windows requires a device driver be present for any device in order to access it. It has some generic drivers, typically for storage devices such as CompactFlash readers and external hard drivers. For communication devices, the vendor must supply a device driver.
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\USB
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4D36E978-E325-11CE-BFC1-08002BE10318}
is ports
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4D36E96D-E325-11CE-BFC1-08002BE10318}
is modems
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Ports
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\COM Name Arbiter
COMdb key is a bitmask of which com ports are in use (8 ports per byte). Set to 3 to reserve com1 and com2
BitPim Online Help built 27 December 2006