[ntp:questions] YEA! My Sure Electronics GPS just arrived.

DaveB g8kbv at uko2.co.uk
Mon Mar 26 13:27:33 UTC 2012

In article <sdp549-8mj.ln1 at klein-habertwedt.de>, uwe at klein-habertwedt.de 
> DaveB wrote:
> > Ron.  To "fix" wandering com ports in Windows, take a look at:-
> > https://fedorahosted.org/fldigi/wiki/Documentation/HOWTO/Windows_USBSeri
> > al
> The most irritating issue I found under linux is that
> most manufacturers of commodity stuff like serial USB adapters
> don't programm serial numbers into their devices.
> Having a bunch of serial lines to different physical devices
> mapped in random is a major bother.
> ( One solution is to attach them in fixed order to one hub.
>     then attach the hub.
>     ports on one hub always seem to have the same enumeration order )
> uwe

There is some sort of unique ID.  As, if you do the trick to nail a 
Virtual COM port to say, COM4 while using one particular USB<>RS232 
device.  Remove it, and re-plug to check it comes back as the same port.

But then connect an identical device, from the same maker etc, in that 
same USB socket, Windows (at least) will decide it's new hardware and 
you'll have to go round the loop again.

There is a unique ID in there somewhere, that along with the hub(s) it's 
attached via, form a unique instance ID.   In that respect, USB is a bit 
like a network, where there are unique MAC addresses (yes, I know they 
can be cloned by some devices....)

Just that it's not brought out in any UI for us to use.


Dave B.

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