C# Definition:

public enum RtsControl : int
{
    /// <summary>
    /// Disables the RTS line when the device is opened and leaves it disabled.
    /// </summary>
    Disable = 0,

    /// <summary>
    /// Enables the RTS line when the device is opened and leaves it on.
    /// </summary>
    Enable = 1,

    /// <summary>
    /// Enables RTS handshaking. The driver raises the RTS line when the "type-ahead" (input) buffer
    /// is less than one-half full and lowers the RTS line when the buffer is more than
    /// three-quarters full. If handshaking is enabled, it is an error for the application to
    /// adjust the line by using the EscapeCommFunction function.
    /// </summary>
    Handshake = 2,

    /// <summary>
    /// Specifies that the RTS line will be high if bytes are available for transmission. After
    /// all buffered bytes have been sent, the RTS line will be low.
    /// </summary>
    Toggle = 3
}

VB Definition:

Public Enum RtsControl As Integer
    Disable = 0
    Enable = 1
    Handshake = 2
    Toggle = 3
End Enum ' RtsControl

Notes:

None.