RTS - request to send
CTS - Clear to send.
those are flow control signals. how you use them depends on whether you are implementing a terminal (DTE) or a computer (DCE). For a DTE, you want to send something, you raise RTS and wait for CTS to be raised.
note that the ethernet device also supports xon/xoff flow control. might be easier.
what does the EGSR7150MJ cost? I could only find an eval kit price ($190). I've used the xport - it's $50. don't really need an eval kit for it - I made my own board.
edit: I found it. wow. $34 USD, not bad. That's worth buying to check out. supposedly supports 100 mhz though that's unlikely to matter much as the max serial speed is 230K.