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microsoft.public.dotnet.framework

VB.Net 2005 and serial coms

Tym

9/19/2008 11:01:00 AM

Usually Dick Grier responds to these kind of messages... ;-)

Is there a way (preferably an easy one!) to detect the supported baud rates
of a given serial port???

Some coms devices I'm using work fine at 115200, others need to be at
460800, and I need to detect the available baud rates to see whcih one I
have in place.

If I select the different devices in Hypertemrinal, it will list the bauds
available, so surely I can pick them out from somewhere...?


Tym.


3 Answers

Tym

9/19/2008 11:17:00 AM

0

And If I can add a very simple further question,

What does ctsfl=1, rtsctl=2 mean?

In vb what are the equivalent CTS and RTS settings?

"Tym" <spamtrap@ictis.net> wrote in message
news:xdGdncUs4ZMZG07VRVnyvwA@posted.plusnet...
> Usually Dick Grier responds to these kind of messages... ;-)
>
> Is there a way (preferably an easy one!) to detect the supported baud
> rates of a given serial port???
>
> Some coms devices I'm using work fine at 115200, others need to be at
> 460800, and I need to detect the available baud rates to see whcih one I
> have in place.
>
> If I select the different devices in Hypertemrinal, it will list the bauds
> available, so surely I can pick them out from somewhere...?
>
>
> Tym.
>


Dick Grier

9/22/2008 4:05:00 PM

0

Hi,

No, there is no way that I know to determine maximum serial speed, except
through the manufacturer's documentation.

CTS and RTS (Clear to Send/Ready to Send) are hardware handshaking lines
that are used -- in hardware implementations, not generally software/virtual
serial ports -- to avoid data loss. The sending system monitors CTS to
determine if it can send data, where HIGH indicates that it is OK to send.
The receiving system LOWERS RTS to signal that the sending system should not
send data until RTS is returned high. A common implementation "cross
connects" RTS and CTS, between sender and receiver, so that these two line
complete this signalling method.

In DesktopSerialIO, which you are using, hardware flow control is handled by
the .CTSHandshaking property. You enable it by setting .CTSHanshaking =
True. Since you are using a modem, this is good practice. The dll itself
handles the details for you. You can set RTSEnable = True, and leave it
with this setting, so that the dll operates without interference.

Dick
--
Richard Grier, MVP
Hard & Software
Author of Visual Basic Programmer's Guide to Serial Communications, Fourth
Edition,
ISBN 1-890422-28-2 (391 pages, includes CD-ROM). July 2004, Revised March
2006.
See www.hardandsoftware.net for details and contact information.


Dick Grier

9/23/2008 4:13:00 PM

0

Tym,

Actually, I remebered that System.Management does have a MaxBaudRate value
that my prove to be useful. I've sent you the code that I have for this
from my book.

Dick

--
Richard Grier, MVP
Hard & Software
Author of Visual Basic Programmer's Guide to Serial Communications, Fourth
Edition,
ISBN 1-890422-28-2 (391 pages, includes CD-ROM). July 2004, Revised March
2006.
See www.hardandsoftware.net for details and contact information.