The following functions are used with communications resources:
| To . . . | Use this system call . . . | 
|---|---|
| Restore character transmission for a specified communications device and place the transmission line in a nonbreak state | ClearCommBreak | 
| Retrieve information about a communications error and report the current status of a communications device | ClearCommError | 
| Close a communications device handle | CloseComm | 
| Direct a specified communications device to perform an extended function | EscapeCommFunction | 
| Cause all buffered data to be written to a communications device | FlushCommBuffers | 
| Retrieve the current configuration of a communications device | GetCommConfig | 
| Retrieve the value of the event mask for a specified communications device | GetCommMask | 
| Retrieve modem control-register values | GetCommModemStatus | 
| Retrieve information about the communications properties for a specified communications device | GetCommProperties | 
| Retrieve the current control settings for a specified communications device | GetCommState | 
| Retrieve the time-out parameters for all read and write operations on a specified communications device | GetCommTimeouts | 
| Open a handle to a communications device | OpenComm | 
| Discard all characters from the output or input buffer of a specified communications resource | PurgeComm | 
| Read data from a communications device | ReadComm | 
| Reset a particular communications device event | ResetCommEvent | 
| Suspend character transmission for a specified communications device and place the transmission line in a break state | SetCommBreak | 
| Set the current configuration of a communications device | SetCommConfig | 
| Specify a set of events to monitor for a communications device | SetCommMask | 
| Configure a communications device according to the specifications in a device-control block | SetCommState | 
| Set the time-out parameters for all read and write operations on a specified communications device | SetCommTimeouts | 
| Initialize the communications parameters for a specified communications device | SetupComm | 
| Transmit a specified character ahead of any pending data in the output buffer of the specified communications device | TransmitCommChar | 
| Wait for an event to occur for a specified communications device | WaitCommEvent | 
| Write data to a communications device | WriteComm | 
Drivers include:
| Description | Driver | 
|---|---|
| Driver for the onboard PC COM ports. | compc.rta | 
| Driver for the Comtrol family of Advantech serial multi-channel PCI cards. | comadv.rta | 
| Driver for the Comtrol family of RocketPort serial multi-channel PCI cards. | comrocket.rta | 
| Driver for the Comtrol family of Moxa serial multi-channel PCI cards. | commoxa.rta | 
| Driver for the serial multi-channel PCI cards based on the Moschip/AIX 9900/9912 controllers. | commoschip.rta | 
| Driver for the Digi International Edgeport line of USB multi-channel serial device. | comedge3.rta | 
| Driver for the FTDI USB serial device. | comftdi3.rta | 
Utilities include:
| Description | Utility | 
|---|---|
| Displays the name and status of all COM ports. | comlist.rta | 
The following structures are used with communications resources:
| Description | Structure | 
|---|---|
| Contains information about the configuration state of a communications device. | COMMCONFIG | 
| Used in SetCommTimeouts and GetCommTimeouts to set and query the time-out parameters for a communications device. The parameters determine the behavior of ReadComm and WriteComm operations on the device. | COMMTIMEOUTS | 
| Used by GetCommProperties to return information about a given communications driver. | COMMPROP | 
| Contains information about a communications device. This structure is filled by ClearCommError function. | COMSTAT | 
| Defines the control setting for a serial communications device. | DCB |