Serial provides device control requests to control the operation of serial devices that support a 16550 UART-compatible interface.

Serial supports IOCTL_SERIAL_Xxx requests that a client can use to perform the following tasks:

• Get and set control registers and control signals.
• Get and set line control and modem control.
• Set FIFO control.
• Get and set handshake and flow control operation and parameters.
• Get and set wait events.
• Purge internal buffers, set the receive buffer size, and reset the device.
• Get and set timeouts that are used for read and write requests.
• Get and clear performance statistics.
• Get status information.
• Get properties of the device.

Serial supports IOCTL_SERIAL_INTERNAL_Xxx requests that a trusted kernel-mode client can use to perform the following tasks:

• Set basic settings on a device and restore previous settings.
• Disable and enable the wait/wake operation of a device.

For more information about the high-level operation of COM ports, see the information about the communication resources that are supported by the Windows Base Services in the Microsoft Windows SDK.

For more information about Serial I/O requests, see Serial Driver Reference.