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Carrier Detect dropped with Null Modem cable ?

Posted on 2001-07-10
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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
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Question by:nvms
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Expert Comment

by:inthedark
ID: 6270849
Is the a comm control question?  In which case what are your port/handshaking settings?
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by:nvms
ID: 6271582
9600,N,8,1 None (the remote dial-up hardware does not have hardware handshaking)...  
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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.

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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

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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.

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