[GreenKeys] HRS312 TTY Interface

[Jon Schlegel]

Hi All,

USB to Serial interfaces in regard to TTY is a confusing issue to 
which I thought I'd add!  Duncan K2OEQ and myself recently went 
through an exercise at the Antique Wireless Association to test out 
the HSR312 MOS switch as a loop keyer.  We used MMTTY as the TTY 
source running on a Windows XP laptop that has no serial 
ports.  MMTTY supports a USB to Serial feature but only when the 
specified Belkin F5U103 USB to Serial converter is used.

My friend Jamie KF2B who is involved with USB hardware on pretty much 
a daily basis noticed that the Belkin converter did not use the 
typical single chip solution that so many of the converters do use 
(e.g. Silicon Labs CP2102).  The Belkin converter instead uses some 
other multiple chip solution.  From this information I've taken a 
giant leap of faith and am guessing that this alternate hardware 
allows MMTTY to manipulate the Belkin hardware in a way far different 
than the usual serial<>parallel conversion that a typical UART provides.

This would make MMTTY very hardware dependent on the Belkin converter 
with no guarantee that it would work in the same manner when driven 
by software other than MMTTY.


Sidebar - WINDOWS XP - 98

WinXP
After some experimentation, I found like there is a probably a lower 
baud rate limitation for serial ports on Windows XP of 50 
baud.  Leaving out details, it looks to be a Windows XP driver 
limitation rather than some sort of hardware limitation.  It also 
appears that properly written application software that utilizes the 
Windows XP serial port driver is supposed to enumerate capabilities 
of the serial port driver for use by application software.

If this is the case then the existing XP serial port driver would not 
allow 60 speed operation at 45.45 baud.  I'm not a software guy but 
it would seem that running outside existing driver limitations would 
need a new driver to be written that allows arbitrary com port 
parameters to be set.  No mean task to say the least

Win98
It's more likely that things can be twisted around on Win98 (e.g. 
"Baudshim" and others) and Windows 98 may be a better platform than 
XP for coping with these odd requirements.

Is there is anyone who can help out on this?


Regards,
Jon Schlegel WA3MVM


At 09:57 AM 3/20/2009 -0400, you wrote:

>On Mar 18, 2009, at 12:34 PM, Andrew Hager wrote:
>
> > Hi,
> >
> > Long time looker, first time poster.  I saw this post and have
> > thought about
> > using the HRS312 in conjuntion with one of these:
> >
> > http://www.hobbyengineering.com/H1516.html
> >
> > None of my computers have serial ports anymore
>
>Andy,
>
>One point to be aware of is that some USB to serial port adapters will
>not run slow enough to do teletype signals.  This has been brought out
>in the past here on the list.  I don't have any details, but no doubt
>Gil and others will have both information and experience to share.
>
>Roy
>
>
>Roy Morgan
>k1lky at earthlink.net
>529 Cobb St.
>Groton NY, 13073
>
>
>
>
>
>______________________________________________________________
>GreenKeys mailing list
>Home: http://mailman.qth.net/mailman/listinfo/greenkeys
>Help: http://mailman.qth.net/mmfaq.htm
>Post: mailto:GreenKeys at mailman.qth.net
>
>This list hosted by: http://www.qsl.net
>Please help support this email list: http://www.qsl.net/donate.html