Thanks for all that. I have two types of cable kicking about the workshop. Both have the same 'recommended' chipset but one is in the RS232 and the other type has it in the USB, both have fly leads at the other end. I would prefer to use the cable with the chip in the USB with the 4 ends, +, -, Data+ and Data-. I will await Ian's comments when he has seen a lead. Cheers. John