- Please suggest a solution to configure virtual com port over USB 2 type A so that the software may communicate with the device through USB port. Note that device manager does not show any USB-to-serial devices even with variable 'devmgrshownonpresentdevices=1'.
- It is possible to override this behaviour to make the system ignore a device's serial number and treat all devices with matching VID and PID connected to the same USB port as if they were the same device. This is achieved by adding a REGBINARY value called IgnoreHWSerNum to the registry and setting it to 01.
If this value is non-zero or does not exist, then the serial number is generated uniquely per device. CurrentConfiguration: REGSZ: OEM: This string must correspond to the name of a configuration subkey. This string determines which configuration to use to build a configuration descriptor for USB device enumeration.
This topic describes the device-specific registry entries.
Find device information after it enumerates on Windows
View the device interface GUID, Hardware Id, and device class information about your device
Find this registry key and note the DeviceInstance value:
HKEY_LOCAL_MACHINESYSTEMCurrentControlSetControlDeviceClasses
Find the device instance registry key and get the device interface GUID:
HKEY_LOCAL_MACHINESYSTEMCurrentControlSetEnumUSB<hardware id><instance id>Device Parameters
Under the device instance key, note the device class, subclass, and protocol codes:
HKEY_LOCAL_MACHINESYSTEMCurrentControlSetEnumUSB
Registry settings for configuring USB driver stack behavior
The registry entries described in this topic are found under this key:
Usb Drive Serial Number
In the vvvvpppprrrrr key,
- vvvv is a 4-digit hexadecimal number that identifies the vendor
- pppp is a 4-digit hexadecimal number that identifies the product
- rrrr is a 4-digit hexadecimal number that contains the revision number of the device.
The vendor ID, product ID, and revision number values are obtained from the USB device descriptor.The following table describes the possible registry entries for the vvvvpppprrrrr key. The USB driver stack considers these entries as read-only values.
| Registry entry | Description | Possible values |
|---|---|---|
osvc REG_BINARY Supported on Windows XP and later versions. | Indicates whether the operating system queried the device for Microsoft-Defined USB Descriptors. If the previously-attempted OS descriptor query was successful, the value contains the vendor code from the OS string descriptor. |
|
IgnoreHWSerNum REG_BINARY Supported on Windows Vista and later versions. | Indicates whether the USB driver stack must ignore the serial number of the device. |
|
ResetOnResume REG_BINARY Supported on Windows Vista and later versions. | Indicates whether the USB driver stack must reset the device when the port resumes from a sleep cycle. |
|