Data type Range Default value
REG_DWORD 0 | 1 1


A value of 1 indicates that the system has copied the entries in this Serial# subkey to the port's device-specific subkey in the Enum subkey (HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum). (The system does not set the value of this entry to 0.) After using this entry to mark that it has transferred the data, the system no longer reads this subkey.

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In Windows NT 4.0 and earlier, each Serial# subkey stored settings an individual serial ports. The settings in the Serial# subkeys took precedence over default settings for all serial ports in the Serial subkey. In Windows 2000, settings for individual ports are stored in device-specific subkeys of HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum.

If you have upgraded from Windows NT 4.0 and earlier, Serial# subkeys might still appear in your registry, but after the values they contain are copied to Enum, these subkeys are no longer used.

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