And no, a USB to serial converter arrangement will not work with the program so the later/newer/newest Laptops with USB only cannot do it, only DB9 serial.

Actually, you *can* do it with a USB to serial converter, as long as you set the COM port number correctly. Have used one myself to update a RFM. I think the problem is that most converters default to the wrong COM port and the Pin2k update software gets confused.

Haven't used a prism card before, but have updated 3 RFM using an old desktop that had a serial port and a null modem cable (jaycar). Found the update software quick and easy to use. ymmv