To support automatic detection of docking events for removeable serial port hardware, serial port drivers can monitor the Data Carrier Detected (DCD) line. For any serial port which is subject to automatic detection, such as PC Card–based serial port hardware, the driver can use the CeEventHasOccured function to watch for the NOTIFICATION_EVENT_RS232_DETECTED message. When such a message occurs, the user has docked a serial port. Some Windows CE–based platforms that support Direct Cable Connect synchronization services starts the synchronization services when this event occurs. See Platform\Odo\Drivers\Serial\p2io.c for an example of detecting this message.