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Open Serial Port (script step reference)

By July 1, 2023July 17th, 2023Online Help, Troi Serial Plug-in
Troi Serial Plug-in for FileMaker Pro

Open Serial Port

Opens a serial port with this name and the specified parameters.

SyntaxScript step badge

Open Serial Port [ Select ; Result (error) ; Port name ; Settings ;
                   File name ; Script name ; Resume paused script ;
                   No idle wait time ; Match string ]


Select entire contents replaces the entire contents of a field with the result. If not checked the result replaces the currently selected portion of the field
Result (error) an error code
Port name the name of the port to open
Settings (optional) specifies the setting of the port like the speed of the port, parity, etc.
File name (optional) the name of the FileMaker file which contains the script to trigger when data comes in
Script name (optional) specifies the name of the script to trigger when data comes in
Resume paused script when the trigger script needs to run, and an other script is already paused, the paused script will resume after the trigger script is finished
No idle wait time don’t add idle wait times, the triggering will be faster, but the plug-in will need more computer time
Match string (optional) a string that must be matched before the script is triggered

Returned Result

Data type returned

Error code


Returned result is an error code. Returned error codes can be:

0 no error the port was opened
$$-50 paramErr there was an error with the parameter
$$-108 memFullErr ran out of memory
$$-97 portInUse could not open port, the port is in use
$$-4210 portDoesNotExistErr port with this name is not available on this computer
$$-4211 allPortsNullErr no serial ports are available on this computer

Other errors may be returned.

Originated in

Troi Serial Plug-in 5.0


FileMaker Pro 16 to FileMaker Pro 2023


If you specify a filename and scriptname any scripts specified with the function “Serial_SetDispatchScript” will be ignored for this port.

If you specify a filename you must also provide a script name.

Version 6.0 added the (optional) Match string parameter, you can now specify directly when opening a port the string for which the plug-ins waits before triggering a script.


Open Serial Port [ Select ; $ErrorCode ; "COM2" ; 
                   "baud=19200 parity=none  data=8 stop=10 " &
                   "flowControl=DTRDSR  flowControl=RTSCTS" ;
                   "" ; "" ]

will open the COM2 port with a speed of 19200 baud and the specified options.

Example 2

Set Variable [ $Settings ; gSpeed & " " & gStopBits & " " & gDataBits & " " &
                          gParity & " " & gFlowControl ]

Open Serial Port [ Select ; $ErrorCode ; 
                   gPortName1 ;
                   Get ( FileName ); 
                   "Process Data Received for 1st Port" ]

Set Field [ gErrorCode ; $ErrorCode // also save into a field ]

This will open the port in field gPortName1 with the specified speed and other options. When data comes in the script “Process Data Received for 1st Port” in the current filename will be triggered. An error code is set in the $ErrorCode variable and also saved into a global field.

Used in example file


Related script stepsScript step badge

Close Serial Port
Set Serial Direct Insert
Set Serial Trigger Script

Related functionsFunction badge


Related topics

Troi Serial Plug-in online help (overview)

Online Help Page for Troi Serial Plug-in for 16 to 2023 –> Open Serial Port (serip7805) 2023-0717 13:12:05