afremont:
I don't know where you get that idea from, but please check this link:
RS-232 vs. TTL Serial Communication - SparkFun ElectronicsThe RS232 voltage level signal IS inverted from the TTL level version.
True, but if his cable outputs the inverted signals then it won't work with any known RS232 device. Somewhere in the cable it has to invert them before they reach the pins.