Help ! Capturing IO from a com port


Thread Starter


Hi folks. Hope someone can help me on this: My company use a Windows based application called Winpak, which is mainly used to buffer / unbuffer security alarm panels. This is done via a modem on COM1 connecting at, yes, 1200 Baud !!! One of my collegues has to dial into about 30 clients everyday just to perform the unbuffer process - V. Tedious. What I'd like to be able to do is monitor exactly what the application is sending down the modem and what it receives back from the panels via the customer's modem. Maybe then I can write something that'll just run through a list of phone numbers and automatically perform this particular feature of Winpak. Any ideas? Any software ( pref. free ) that'll do this? Everything I've downloaded so far has been no good... Many thanks in advance -Dave.
Hi Dave, You can easily do this by hooking up another computer with two serial ports, just connect RxD from each of the two ports to the TxD and Rxd lines of the modem or the computer running the software. Then you can start up two HyperTerminal sessions with the two com ports (config as direct connect, no modem), and see exactly what's coming over the line. Remember to hook up at least one ground between the two computers. If it's straight text, this will work fine. If there are any characters that are not visible ASCII, you'll have to find a terminal program that displays invisible characters as some kind of text. That shouldn't be too tough, I used to have a terminal that would display tiny symbols like : LF, CR, AK, etc. for each received character. If you can program, you could even write a simple app that opens both comm ports in this manner and save the data off to a file. This would have the advantage of showing the dialog. One other thing...on one system I had to reverse engineer, the host sent a hidden control character at random intervals. The remote had to answer back with another control character within a certain amount of time, or the host would disconnect. Since this is a security system, it wouldn't surprise me if there were something similar in this protocol. Regards, Willy Smith Numatics, Inc. Costa Rica
I've used a product from Frontline Test Equipment that lets you capture asynchronous serial data. You can view the data in ASCII, hex, binary, etc. It's proven very useful in the past to do just what you want to do, as well as troubleshoot modbus and other serial comm problems with custom apps. Their website is, and their phone number is (804)984-4500. If memory serves the software was only about $200 - $300. Well worth the money for what you get. Brady Matherne PLC / SCADA Tech Panel Specialists, Inc. [email protected]

Christian Felde

You could try and connect a second computer. Connect the first computer to COM1 on the second computer, and the modem to COM2, also on the second computer. Then make a script/program/whatever witch routes all data from COM1 to COM2, and from COM2 to COM1. Including with this routing, you make it save all data to a log.
With RS232 you can monitor the TX and RX lines using two com ports on another PC. This way com1 on the testing pc listens to the RX line of the conversation, and com2 of the test pc listens to the TX line. The data you are testing is not changed this way. I used some shareware to do this, with an adapter made from Radio Shack parts that cost about $20. It worked well. Unfortunately, the shareware seems to have been pulled from all the shareware sites, and I was never able to have the programmer return my calls so I could pay him. See if you can find: RS232 Version 1.01 Ring Development Maple Grove, Minnesota Ed Speaking for me, not for Starbucks. . .

Duncan Thomson

Dave, A couple of ideas, you could try PortMon from . This captures all commands send to the windows comms routine. Downside is that it captures more thaan you usually want to see and the formatting seems to be unconfigurable. Another option would be to use EasyCom . The help file contains instructions on how to make a monitor cable which plugs in between the serial port and the modem. You can then use two com ports on a remote computer to monitor all comms in and out... Easy to use and quite configurable, also displays in hex or ascii, and separates incoming from outgoing messages. Someone may have better solutions, just some ideas to get you started. hope this helps Duncan

Peter Veselosvky, konnexis

You can download a free "Protocol Analyser" software from the Internet. I use one that runs on an old Toshiba lap top with two serial ports. You can also rent protocol analyser (for serial port only - should be quite cheap) Compared to a hyper terminal, protocol analyser will tell you what is going on with hardware control lines, as well as what is the timing (delays synchronization) of data being sent and received. Peter Veselovsky, P.Eng [email protected]
hi guys If u want to access io from com port there are two option available to u : 1. use MSCOMM control with VC++/VB 2. use Win32 API (for this use CreateFile(), GetCommState() , SetCommState() etc.. Available in MSDN under Communication function (Win32 API) Using MSCOMM will be easier (if u have good hold on VC++ / VB . Both support this control) Best of luck
>Dave, A couple of ideas, you could try PortMon from . ... Another option would be to use EasyCom . &lt;clip><

I would use EasyCom Someone may have better solutions. But I have a problem. I do not known where I can purchase a licence for EasyCom. The address gives no response.

Can you help me and give useful information where I can buy a licence or what is the new link from this enterprise or the adress of the

Erich Radzio

CLONDIAG Chip Technologies
Löbstedter Str. 105
07743 Jena, Germany
Phone ++49 3641 594760
Fax ++49 3641 594720
e-mail [email protected]