Pen packet data types are identified by the constants in the following table.
| Constant | Description | Value |
|---|---|---|
| DT_OEM | Indicates an interrupt-time message returned by the virtual pen driver to the pen driver if OEM-specific information needs to be serviced. | 0x00000400 |
| DT_OORPENPACKET | Indicates an interrupt-time message returned by the virtual pen driver to the pen driver if an out-of-range pen packet generated the interrupt. | 0x00000004 |
| DT_PENPACKET | Indicates an interrupt-time message returned by the virtual pen driver to the pen driver when the virtual pen driver gathers a complete pen packet. | 0x00000001 |
| DT_TIMERTICK | Used internally by the timer tick callback routine. | 0x00000002 |
| DT_UPDATEPENINFO | Sent to all pen driver clients if the pen information structure changes. | 0x00000008 |