Help opening COM ports over 9...

USB Devices
1

I’m trying to open com ports over 9 with my 16 port edgeport…

I’ve tried \.\COM13
No luck

I’ve tried
.COM13
No luck, I’ve added :'s to the above, still no opening…Hyperterminal DOES open it and talk to it!
I’m doing a
CreateFile(“\.\COM13”,GENERIC_READ|GENERIC_WRITE,0,NULL,OPEN_EXISTING,0,NULL);
it fails.

HELP!! I have com ports all the way in the 25 range I have to code to!

2

Which Windows operating system do you have?

3

I’m using XP home edition, with all patches installed…

my createfile line has a “\\.\COM11” double backslashes so it makes a correct string of \.\COM11

Thanks!

4

My guess is that your application is a 16-bit app, and therefore can’t access com ports 9 or above. See details for Windows 98 in the following article:

http://www.digi.com/support/kbase/kbaseresultdetl.jsp?id=153

I realize you have Windows XP, but it doesn’t seem like XP has the problem since Hyperterminal (a 32-bit app) can access them just fine. My guess is with the application itself.

5

You could be missing a"".
At this link:
http://msdn2.microsoft.com/en-us/library/aa363858.aspx

It has this annotation:
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.

It could also be that you are using an older or outdated programming language version or one which requires extended com libraries such as what you may find at http://www.sax.net/