Hi All
Miracle of miracles, now seems to be working.
Thanks go to Geek, who pointed me in the right direction, although not quite sure it was intentional.
Anyway, Geek.
Not sure the downloads you pointed me to were for the dongle or the unit software. Also, did you try looking at the Installation Driver file.
Doubt you did because you would have found it was in French!!!
Thank god for translation software. Here's the text:
'For win 8 it is necessary to uninstall all trace of other driver Prolific PL2303 because the chipset used here is old and no longer maintained for the win 8 version.
It is necessary to install the old driver Vista or seven, version 1.5
After installation you plug your dongle, it will be recognized but will not work a small yellow triangle appears on it in the device manager.
You can right click on the "Prolific USB-to-Serial Comm Port" device and do "Update driver" and choose "Choose a driver on my computer" then "choose from a list of drivers on my computer" and there in The list you select Prolific USB-to-Serial Comm Port: 3.4.25.218 [07/10/2011]
There you do next and it's won; o))'.
Doesn't make sense as you will find out.
I have a number of dongles, so I didn't mind bricking one in the cause of science.
So, uninstalled current PL2303 drivers. Followed the instructions to the letter. When I got to the stage 'choose from a list of drivers' quite surprised to find I had a choice of three, considering I had uninstalled them. Not quite such a surprise to find that none of them matched the file quoted in the instructions.
I had 2009,2010 and 2017.
On the basis I was working with old chips, chose the 2009 one. Not sure whether I have updated the drivers for the software or the dongle, or maybe neither. To be honest, don't much care.
However, something else came up during this which might have a bearing.
Started off by opening the software first, and the drop down menu on there gave me a choice of Com1 or com2.
Needless to say pc wouldn't talk to the unit. What I did find was that if I plug the dongle into the pc first then fire up the software, it automatically gives me Com3 and will then connect.
So, conclusions.
Could it be so simple that I just need to plug the dongle in first? If so, should be kicking myself. Anyway, no matter. All I need is to check it's still working when I need it for real.
Might have found the answer by accident, but still owe you all a big thankyou for your contributions. Great bunch.
Cheers
Jeff