Setting Read and Write Timeouts for a Serial Device
A client can use an IOCTL_SERIAL_SET_TIMEOUTS request to set time-out values that the system-supplied Serial.sys driver uses for read and write requests. Serial.sys continues to transfer bytes until the requested number of bytes are transferred or a time-out event occurs.
The time-out operation in Serial.sys is compliant with the user-mode operation of COM ports that is supported by the communication functions that are supported by the Windows Base Services in the Microsoft Windows SDK.
Note that the time-out operation is not applied to a pending request while it is queued. The time-out operation is applied to a request after the request becomes current (that is, Serial.sys starts to process the request).
For more information about the read and write time-outs, see the following:
The SERIAL_TIMEOUTS structure in the Ntddser.h header file in the Windows Driver Kit (WDK).
The SetCommTimeouts function and the COMMTIMEOUTS structure that are supported by the Windows Base Services in the Windows SDK.