The device driver does not provide any capabilities of event notification. For example, the only way for an application to know that RI changed state or that a Break condition occurred is to poll that status with the IOCtl ASYNC_GETCOMMEVENT. This should not be a problem for those applications that can use the automatic control modes of the physical device driver during the course of a communications dialog (for time-critical control functions). Polling could be adequate for non-time-critical event monitoring.