How to: Send Strings to Serial Ports in Visual Basic

This topic describes how to use My.Computer.Ports to send strings to the computer's serial ports in Visual Basic.


This example sends a string to the COM1 serial port. You may need to use a different serial port on your computer.

Use the My.Computer.Ports.OpenSerialPort method to obtain a reference to the port. For more information, see OpenSerialPort.

The Using block allows the application to close the serial port even if it generates an exception. All code that manipulates the serial port should appear within this block or within a Try...Catch...Finally block.

The WriteLine method sends the data to the serial port.

Sub SendSerialData(ByVal data As String)
    ' Send strings to a serial port.
    Using com1 As IO.Ports.SerialPort = 
    End Using
End Sub

Compiling the Code

  • This example assumes the computer is using COM1.

Robust Programming

This example assumes the computer is using COM1; for more flexibility, the code should allow the user to select the desired serial port from a list of available ports. For more information, see How to: Show Available Serial Ports.

This example uses a Using block to make sure that the application closes the port even if it throws an exception. For more information, see Using Statement.

See Also

How to: Dial Modems Attached to Serial Ports
How to: Show Available Serial Ports