Spy on comm port using VB

Posted on 2004-09-09
Last Modified: 2012-06-27
I would like to spy (peek, sniff, capture, redirect) data sent to a comm (RS232) port from an existing application that cannot be modified for purposes of modifying that information into a new data stream for export to another RS323 port. I have a navigation program that sends out  tracking information through an RS232 port using the newer NMEA 0183 protocal. I would like to modify this data to an older NMEA 0180 protocal so that my vintage auto pilot will accept it. I am looking for a VB 6.0 preferrable application. the application cannot interfere with the communications, it should only be able to read the data being sent out the RS232 port.
Question by:Vincentpiraino
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 2
  • 2
  • 2
LVL 14

Expert Comment

ID: 12030032
Need an extra port for this.
Connect two ports whit a null modem cable. One of these would be the formal output. Then you can set up two MS Comm controls in VB app and get access to data in middle and send it to third port after modifications.



Author Comment

ID: 12043327
Unfortunately, this and many newer laptops are coming without any RS232 ports; I need a non-hardware dependant solution, thank you for your post Matti.
LVL 32

Expert Comment

ID: 12045493
If your existing application allows you to select a serial port, then you could use a virtual serial port driver to redirect the data to your application (in theory).  These are third party drivers and it seems there are many out there, some costing more than others.

Here is one example:

Hope it helps!
Independent Software Vendors: We Want Your Opinion

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

LVL 14

Expert Comment

ID: 12047579

Won't found these on VB
Here is on but it's developed on Win2000 DDK and VC++

It's GPL opensource, not a demo.

LVL 32

Accepted Solution

Erick37 earned 500 total points
ID: 12047811
Right, device drivers aren't written in VB (thank God).  I'm suggesting finding a (shareware or cheapware) utility which will allow the data from one virtual port to be directed to another virtual port.  If the existing application allows the user to select comm5 for example, this should work.

another example:
Virtual Serial Ports Driver XP 4.5

Author Comment

ID: 12048850
Erick37, thanks for your solution, not exactly what I was looking for but it will work, solutions range $69-$99 and come with their own SDK, pretty neat, thanks.

Featured Post

Free Tool: Port Scanner

Check which ports are open to the outside world. Helps make sure that your firewall rules are working as intended.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

There are many ways to remove duplicate entries in an SQL or Access database. Most make you temporarily insert an ID field, make a temp table and copy data back and forth, and/or are slow. Here is an easy way in VB6 using ADO to remove duplicate row…
If you have ever used Microsoft Word then you know that it has a good spell checker and it may have occurred to you that the ability to check spelling might be a nice piece of functionality to add to certain applications of yours. Well the code that…
Get people started with the process of using Access VBA to control Outlook using automation, Microsoft Access can control other applications. An example is the ability to programmatically talk to Microsoft Outlook. Using automation, an Access applic…
This lesson covers basic error handling code in Microsoft Excel using VBA. This is the first lesson in a 3-part series that uses code to loop through an Excel spreadsheet in VBA and then fix errors, taking advantage of error handling code. This l…
Suggested Courses
Course of the Month10 days, 17 hours left to enroll

628 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question