You don't say which library you are using but here is the archive for my SerialEx library which fixes several problems with the original Serial library, including monitoring pin changes. Details in the help in the archive.
To detect CTS changes set EnableOnPinChanged = True and in the OnPinChanged test the state of the CTS property. You could also use a Timer instead.
Thanks for the reply, I am using the original serial library. I also failed to mention this is a DEX communication device. The device only has three wires, RXD, TXD and Ground, pins 2,3 and 5 on a DB9 connector. The DEX communication device is just a serial connector, using a 1/4" RCA phone jack, you plug into a retail stores DEX receiver and then transmit a invoice to the store.
I can transmit the data via a null modem cable and see the data being sent to a terminal software program, so I know that works. The problem is, I need to send a ready to send command (RTS) and then wait for the store to send a CTS signal.
So I am at a loss as to how to proceed. So if someone would provide me with some help I would gladly pay the for their time.
Again thanks agraham for the reply.