Thx Bruce,
I using the one that comes with MicroCode Studio Plus.( mecanique) Version 3.2.0.1.

The only hardware requirments shown in the documentation are at the PIC end, RX, TX and line providing a reset to the PIC. (This is the same hardware in my case for both direct serial cable and USB cable.) The bootloader requests a reset for the PIC, and again this works for the direct serial cable, but nothing happens for the USB cable.)

Thx again,
Mike