I have USB to RS232 cable and the signals on the cable are: 1.GND 2.CTS 3.VCC 4.TXD 5.RXD 6.NC how do these map to T1OUT, R1IN, R2IN, T2OUT
When I was young (about 40 years ago) we used a so-called breakbox to try the different connections on RS232.
Now I suggest to try it, without handshaking.
Pin 5 of the DB9 connector comes to GND
Pin 2 to TXD
Pin 3 to RXD
Maybe you have to switch pin 2 and 3 (if both are DCE). If it does not work you probably have to do something with the handshake signals. Look on the internet and you will find 1000's of suggestions.