Re: Question about RS232 compatibility

From: Hapticz (hapticz_at_email.msn.com)
Date: 08/31/04 

Date: Mon, 30 Aug 2004 22:22:54 -0400

make certain the rs232 protocol cd/rts/cts/rts/dsr is properly setup on the "bad" machines

some modem setups automatically assume full sync operation/ others will take shortcuts and "leave out" some handhsake signals to
simulate "improved speed" (good for handshakng with crc/challenge, but bad for hardware equipment that can only see/expect distinct
data streams)

never assume the setups are identical on all machines ports just because they work ok on internet or lan connects. dedicated comms
to hardware devices can be picky and truly unforgiving.

perhaps u may use a method to step down the rate when problems arise, just as dialup modems do when connecting , to ensure reliable
data connects to phone lines ( & they can be affected by weather/line noise/RF interference that degrade signal patency) 

--
Best regards,
Hapticz
STOP STOP STOP STOP STOP STOP STOP STOP STOP
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"Mike Larson" <MikeTheRed@Hotmail.com> wrote in message news:uXYTFbpjEHA.3456@TK2MSFTNGP12.phx.gbl...
> Hello,
>
> Has anyone encounterd this type of problem?
>
> I created a VB6 program to communicate with a piece of equimpent my compnay
> makes over RS232.  I use an echo character scheme where the sending device
> won't send another character until the receiving device echos back the
> character that was just sent.
>
> On 99% of the computer this works just fine.  On the occasional computer the
> scheme fails, for some reason the echo just breaks down.  It appears that
> the computer either doesn't send out a character in the middle of a stream
> of characters or it just fails to receive the echo.  Could this be hardware,
> could it be a driver, are that any settings for the RS232 port that could
> cause this?
>
> I'm kind of grasping for straws here.
>
> Thanks for any feedback.
>
> Mike
>
>

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