Specify state of RTS pin
You can configure RequestToSend to be on or off. If RequestToSend is on, the Request to Send (RTS) pin is asserted. If RequestToSend is off, the RTS pin is unasserted.
In normal usage, the RTS and Clear to Send (CTS) pins work together, and are used as standard handshaking pins for data transfer. In this case, RTS and CTS are automatically managed by the DTE and DCE. However, there is nothing in the RS-232, or the RS-484 standard that states the RTS pin must to be used in any specific way. Therefore, if you manually configure the RequestToSend value, it is probably for nonstandard operations.
If your instrument does not use hardware handshaking in the standard way, and you need to manually configure RequestToSend, then you should configure the FlowControl property to none. Otherwise, the RequestToSend value that you specify might not be honored. Refer to your instrument documentation to determine its specific pin behavior.
You can return the value of the CTS pin with the PinStatus property. Handshaking is described in The Control Pins.