Solved

Carrier Detect dropped with Null Modem cable ?

Posted on 2001-07-10
5
303 Views
Last Modified: 2012-05-05
Hi... it'll probably jump out when I debug the code but has anyone got a 'must be' answer for the fact that my CD Holding has gone low even though I have a null modem cable attached to another RS-232 device. I know the cable is OK because i have used Terminal.exe (W3.x) and it works fine....

hope someone has an idea

Stu
0
Comment
Question by:nvms
  • 3
  • 2
5 Comments
 
LVL 17

Expert Comment

by:inthedark
ID: 6270849
Is the a comm control question?  In which case what are your port/handshaking settings?
0
 

Author Comment

by:nvms
ID: 6271582
9600,N,8,1 None (the remote dial-up hardware does not have hardware handshaking)...  
0
 
LVL 17

Accepted Solution

by:
inthedark earned 50 total points
ID: 6271635
So how will you control flow betweem the systems:
comm1.handshaking=comNone ' or commxon/xoff

So how will you avoid buffer overflow ?

In the old days you could tell dos to ignore carrier detect in the settings like....
9600,N,8,1,CS0

But this is no longer documented.

0
 

Author Comment

by:nvms
ID: 6271764
Hi !! well for some reason CD is now being detected. Win 2000 being a bugger ? Anyway, I am using an Xmodem protocol (which I am about to post a query on) this sends 128 bytes at a time then waits for a ACK or NAK response. This avoids the problems with buffer overflow. Thanks for your comments..

Stewart

0
 
LVL 17

Expert Comment

by:inthedark
ID: 6272262
You send an invoice to Bill Gates re: language referrence ommissions.  If every body did this MS may be a bit more thorough when creating the documentation.

0

Featured Post

3 Use Cases for Connected Systems

Our Dev teams are like yours. They’re continually cranking out code for new features/bugs fixes, testing, deploying, testing some more, responding to production monitoring events and more. It’s complex. So, we thought you’d like to see what’s working for us.

Question has a verified solution.

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

Introduction I needed to skip over some file processing within a For...Next loop in some old production code and wished that VB (classic) had a statement that would drop down to the end of the current iteration, bypassing the statements that were c…
Introduction While answering a recent question (http://www.experts-exchange.com/Q_27402310.html) in the VB classic zone, I wrote some VB code in the (Office) VBA environment, rather than fire up my older PC.  I didn't post completely correct code o…
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…
Get people started with the utilization of class modules. Class modules can be a powerful tool in Microsoft Access. They allow you to create self-contained objects that encapsulate functionality. They can easily hide the complexity of a process from…

772 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