Communicating by RS-232
The "FTDI friend" is the wrong tool for the job.  What you want is a cheaper, off the shelf USB to RS232 converter from a generic computer or office supply store.

As Gustavo points out, the signaling voltage of the FTDI friend is incorrect - about 3.3v unipolar instead of the higher, bipolar RS232 levels used by just about anything of recent vintage that has a 9-pin serial cable.

However, that's not the only issue.  The "sense" of the logic is also customarily inverted between logic level and RS232-level serial signaling.  So even if there were not a potential damage issue due to the voltage incompatibility, the upside-down data would not be interpretable by a typical receiver. 

It might at first seem ironic that a USB-serial chip packed with a a converter to RS232 levels and a 9-pin connector is cheaper than a module with just a chip and the signals broken out at logic level to wires, but not really, when you consider the size of the market for the two products.