How to access COM12

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3 total messages Started by Helmut Giese Fri, 23 Mar 2007 21:13

#2216

Author: Helmut Giese
Date: Fri, 23 Mar 2007 21:13

16 lines
1366 bytes

Hello out there,
I have a many-year-old application which handles several modems at the
same time. Now the system got once more expanded, I have to deal with
COM ports up to '12' - and I cannot open them:
- Opening with 'COM12' results in error 2: System cannot find file.
- Opening with 'COM12:' results in error 138: Syntax error in file
name.

Note: Both versions (with or without ':') work for e.g. COM1.

What I find infuriating is that stupid Hyperterminal is able to
connect to a modem via COM12 - but I am not :(

Any info or link to the correct syntax would be highly appreciated.
Best regards
Helmut Giese

Re: How to access COM12

#2217

Author: Remy Lebeau (TeamB)
Date: Fri, 23 Mar 2007 21:39

17 lines
1665 bytes

"Helmut Giese" <hgiese@ratiosoft.com> wrote in message
news:4604415e.2029877@forums.borland.com...

> I have a many-year-old application which handles several modems
> at the same time. Now the system got once more expanded, I
> have to deal with COM ports up to '12' - and I cannot open them

That is because you are not opening them correctly.  If you read the
documentation for CreateFile() at MSDN, you will see the following:

    "To specify a COM port number greater than 9, use the following
syntax: "\\\\.\\COM10". This syntax works for all port numbers and
hardware that allows COM port numbers to be specified."


Gambit

Re: How to access COM12

#2218

Author: Helmut Giese
Date: Sat, 24 Mar 2007 10:59

20 lines
1605 bytes

On Fri, 23 Mar 2007 13:39:38 -0800, "Remy Lebeau \(TeamB\)"
<no.spam@no.spam.com> wrote:

Hi Gambit,
>> I have a many-year-old application which handles several modems
>> at the same time. Now the system got once more expanded, I
>> have to deal with COM ports up to '12' - and I cannot open them
>
>That is because you are not opening them correctly.  
Yes, I supposed this to be the case :)

>If you read the
>documentation for CreateFile() at MSDN, you will see the following:
>
>    "To specify a COM port number greater than 9, use the following
>syntax: "\\\\.\\COM10". This syntax works for all port numbers and
>hardware that allows COM port numbers to be specified."
Thanks a lot, you saved me a lot of head scratching - as so often.
Have a nice weekend and best regards
Helmut Giese

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