I email the multitech for DTR pb and here is the answer, i hope it will be useful:
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Hello,
The first thing I would do is go through the ISP.TXT that I attached to this
message. Setup the Dips and Config file. Next, I need to know what
version of firmware you are using in the modems. I am also attaching a self
extracting file that has a readme.txt that walks you through upgrading your
modems firmware. This should take care of your connectivity problems. The
<Loss of DTR is normal for disconnects and you should not worry about that>.
So lets make sure you are following the ISP.TXT and you have current
firmware.
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So, DTR is normal dont worry about it
Regards,
Rania Fakhoury
system administrator
IncoNet