[UK-CONTEST] USB-Serial Adaptors

[Don Beattie]

John,

I'm not an expert on this, but I know one thing I would watch out for.

There are two sort of USB:serial adaptors - self powered and externally 
powered.

I have had no problems with the former, but I think you are limited to two 
com-ports with this design. They get their power from the USB port, of 
course.

With the externally powered types, you get a Wall-wart power supply. If the 
adaptor is powered when you switch on your computer (as it needs to be), you 
can get a whole pile of data junk going down the serial line as the computer 
boots up. I can't remember the exact problem I had, but I know I had to stop 
using an externally powered adaptor a few years ago. It's a kind of 
atch-22  - it needs to be plugged into the computer when it boots so that it 
is recognised, but it needs to be unplugged if it is not to send garbage. So 
you end up needing to unplug the serial ports if there is stuff on them that 
doesn't like garbage. I seem to remember my TX was going into spasms with 
the random keying down the serial lines.

The self-powered ones don't seem to have this problem as, presumably, they 
don't get their power until the computer has done most of its booting up.

Oh - and the other thing I have found is that you need to be careful with 
the adaptor software. I found when I got my EZMaster SO2R box (which itself 
has a built-in USB:serial thingy) that if I did not uninstall the software 
for the normal USB:Serial adaptor, things got very messy, and the ports 
didn't work. This may just have been the particular software and hardware I 
was using, but if yours stop working, check what port software you have 
installed.

This whole thing may not be relevant to you, but I thought I'd mention it, 
just in case.



73

Don, G3BJ






----- Original Message ----- 
From: "John Wayman" <g4drs at btinternet.com>
To: <UK-Contest at contesting.com>
Sent: Tuesday, January 29, 2008 6:44 PM
Subject: [UK-CONTEST] USB-Serial Adaptors


> Hello,
>  What should I know and/or beware of regarding USB-Serial adaptors? Is 
> there much difference, or do I just get one for a fiver on E-Bay and plug 
> the 'mp in?
>
>  Cheers,
>
>
>  John
>  G4DRS
> _______________________________________________
> UK-Contest mailing list
> UK-Contest at contesting.com
> http://lists.contesting.com/mailman/listinfo/uk-contest
>
>
> -- 
> No virus found in this incoming message.
> Checked by AVG Free Edition.
> Version: 7.5.516 / Virus Database: 269.19.15/1248 - Release Date: 
> 28/01/2008 21:32
>
>