Serial Ports Monitor ActiveX Control supports the following standard major I/O requests:
| Function | Brief Description |
| IRP_MJ_CREATE | This request opens a serial device |
| IRP_MJ_DEVICE_CONTROL | This request is used to manage a serial port. For a description of the device control requests supported by Serial ports, see IOCTRL request overview. |
| IRP_MJ_FLUSH_BUFFERS | This request flushes the internal write buffer of a serial device |
| IRP_MJ_INTERNAL_DEVICE_CONTROL | This request sets internal operating modes on a serial device |
| IRP_MJ_PNP | This request is used to query devices and to start, stop, and remove devices |
| IRP_MJ_POWER | This request controls power management |
| IRP_MJ_QUERY_INFORMATION | This request queries the end-of-file information for a serial device |
| IRP_MJ_READ | This request transfers data from a serial device to a client |
| IRP_MJ_SET_INFORMATION | This request sets the end-of-file information on a serial device |
| IRP_MJ_SYSTEM_CONTROL | This request supports WMI requests |
| IRP_MJ_WRITE | This request transfers data from a client to a serial device |
See also