Solved

The wierdest question about modems:40 chars

Posted on 2002-05-28
12
159 Views
Last Modified: 2010-05-02
Try connecting two comps using newvbterm.exe of microsoft, or any other similar program using mscomm. Send exactly 41 or 42 characters.You'll find that exactly 40 characters get transmitted everytime.the last 1,2 chars get deleted from the output buffer.Any other similar numbers,anyone ? Or at least a way to solve the problem...?
0
Comment
Question by:sudeepn
[X]
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
  • 5
  • 3
  • 3
  • +1
12 Comments
 
LVL 16

Expert Comment

by:Richie_Simonetti
ID: 7040109
interesting...
0
 
LVL 1

Expert Comment

by:aaronkempf
ID: 7040800
id try sending some sort of VBCRLF character.

0
 

Author Comment

by:sudeepn
ID: 7041689
Helllllp!!! Anybody!


I found that it sometimes happens with 9/10 chars as well. It sends 8 chars, deletes the last 1/2 chars.

Even VBCRLF sometimes doesnt work. I think the only way to solve the problem is to add random chars at the end. This way it works.
0
Industry Leaders: 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 1

Expert Comment

by:aaronkempf
ID: 7042171
i know of one person you can ask this-- but im sure that he'd make you buyg his backup software in order to get an answer.

www.ultrabac.com
0
 
LVL 1

Expert Comment

by:aaronkempf
ID: 7042174
i know thats kindof a backwards answer-- but its the truth..
0
 

Author Comment

by:sudeepn
ID: 7043692
www.ultrabac.com has nothing to do with this.And this site is not an advertising space for those who dont know how to answer.
0
 
LVL 4

Expert Comment

by:mcoop
ID: 7045613
I haven't tried your setup, but as I have had zero problems with MS-Comm when I use it properly... (and I have made a few mistakes !)

Perhaps you're simply not reading all the characters that are in the receive buffer.

There is no guarantee that a whole message will be delivered when the rx_commevent triggers.  You may have to buffer the input, and concatenate subsequent messages until your delimiter/terminator (e.g. CR/LF) is present... only then can you determine whether the whole message has been transferred (or not).

I only suggest this, as I see many people think that MS-Commm does everything - including read and interpret your data - but sadly this is not the case.

The reason many developers get away with this approach (most times) is that the messages are relatively short and bursty - so the RX buffer never overflows between Rx_comevents.

Good luck, I'd like to hear how this resolves.


0
 

Author Comment

by:sudeepn
ID: 7046382
I found the answer myself...in case anyone in the future gets into a similar problem. Send a few random characters every 1/1.5 seconds. This will ensure that all the data is received at the other end. Wierd answer.But it works, as the question itself is absurd.
0
 
LVL 4

Accepted Solution

by:
mcoop earned 50 total points
ID: 7046518
In the case that sudeepn's comment is the 'solution', then I stand by my earler comment that there is in fact no 'fault' but rather that the user's receive buffer is simply not being handled in the right manner to catch the type of mixed length strings being sent.
0
 

Author Comment

by:sudeepn
ID: 7048493
"...then so be it."
0
 

Author Comment

by:sudeepn
ID: 7048494
"then so be it"
0
 
LVL 4

Expert Comment

by:mcoop
ID: 7048514
Cheers & thanks
0

Featured Post

Revamp Your Training Process

Drastically shorten your training time with WalkMe's advanced online training solution that Guides your trainees to action.

Question has a verified solution.

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

Have you ever wanted to restrict the users input in a textbox to numbers, and while doing that make sure that they can't 'cheat' by pasting in non-numeric text? Of course you can do that with code you write yourself but it's tedious and error-prone …
Article by: Martin
Here are a few simple, working, games that you can use as-is or as the basis for your own games. Tic-Tac-Toe This is one of the simplest of all games.   The game allows for a choice of who goes first and keeps track of the number of wins for…
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…
Show developers how to use a criteria form to limit the data that appears on an Access report. It is a common requirement that users can specify the criteria for a report at runtime. The easiest way to accomplish this is using a criteria form that a…

737 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