Opening a single com port from two or more applications using .net

Question

0.00/5 (No votes)

See more:

I want to open a single com port from two or more applications. can anyone provide a some code or any link for achieving this in .net? I am searching the internet from last two days but, could not find any solution. I know, it is possible, because i have some applications that do this work. But, i have to write this functionality in my own application.

Thanks in advance.

Posted 17-Jan-13 20:25pm

AnkitGoel.com

Updated 17-Jan-13 20:29pm

v2

Add a Solution

Comments

Sergey Alexandrovich Kryukov 18-Jan-13 2:28am

Why?!
—SA

AnkitGoel.com 18-Jan-13 2:33am

i have to trace the communication between an existing application and some manufacturing machine.

lukeer 18-Jan-13 2:56am

Say you had the monitoring software already working, you could as well solder some special man-in-the-middle-three-plug-wire to listen to communication in one direction or the other.

Jochen Arndt 18-Jan-13 3:09am

To trace the communication, use a serial port sniffer / monitor. Using the last three/four words you will get a lot of search hits including free utilities. An example application in C++ can be found here at CP: http://www.codeproject.com/Articles/311159/SIMPLE-SERIAL-PORT-MONITOR. It's not .NET but it explains how monitoring can be done.

AnkitGoel.com 18-Jan-13 3:19am

thanks but, it could not work.

AnkitGoel.com 18-Jan-13 3:19am

it cannot open an already open port.

Jochen Arndt 18-Jan-13 3:32am

An already opened port can't be opened a second time. This can't be circumvented. Therefore, all software sniffers must be started before the port is opened.

What are these 'some applications' that claim to can do that?

AnkitGoel.com 18-Jan-13 4:23am

one of them is HHD Serial Port Emulator

Jochen Arndt 18-Jan-13 5:14am

Thank you for the information. I just tested it and it can monitor opened connections. So you are right that sniffing can be done this way. But it is not done by openening a port a second time (the Windows API CreateFile function used to open serial ports will fail when the port is already opened).

Because this is interesting, I googled a little bit:
http://social.msdn.microsoft.com/Forums/en/csharpgeneral/thread/108d65c6-dcc3-4483-a50c-ac540453f433
From the above:
http://www.drdobbs.com/a-serial-port-spy-for-nt/184416559

I hope this helps and you have some kind of success.

AnkitGoel.com 21-Jan-13 0:06am

Thanks Jochen, did u try this code? Does it work for you?

Jochen Arndt 21-Jan-13 3:28am

No, I did not tried it. It's too complex for a quick implementation.

AnkitGoel.com 21-Jan-13 7:37am

I feel the same and don't have time to get into the depth at this time.

1 solution

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Grasshopper.iics · Accepted Answer · 2013-01-17T20:51:00

Solution 1

You can not have more than one process opening a com port. If port is opened by a process, other process will simply not be able to open it. Best bet is to use simple TCP/IP, open the port from a server program, from other applications, interact with the server.

Posted 17-Jan-13 20:51pm

Grasshopper.iics

Comments

AnkitGoel.com 18-Jan-13 3:02am

AS i already said, i am able to open a port multiple times using a third party application. but i want to do it in my own code to make it user friendly.