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US Robotics Modems Don't Clear


I have a phone dialer as part of a larger app.  The phone dialer is modeled after an example Dialer program that came from Microsoft.   The Microsoft dialer example stops/cancels/ends the dialing operation by sending an ATH + Carrage Return followed immediately by closing the comm port.  (I assuming this may be the problem, but I don't really know what's causing it.)

Even though this does not allow the modem to complete the hangup and report OK, it works on most modems except US Robotics.  

Users with US Robotics modems report that after dialing one number the modem locks up.  They can't dial another number.  Getting out of the program and back in doesn't help.  Some report they must reboot to reset the modem.  Others report going into any other program that uses the modem resets it.  I have tried sending all the commands I can think of to reset it but without success.  

What are the other comm. programs doing that is effective reseting the modem?  Or, what does Windows do during a power on restart that resets it?

1 Solution
Have you tried simply telling the modem to reset to factory defaults just prior to dialing:

AT &F ATDT xxx-yyyy
houstonAuthor Commented:
No.  I have tried doing that after hangup, but not before dialing.

The major problem I've had trying to solve this is, I can't reproduce it myself.  I get the failure reports from remote users who are sometimes willing to try a few tests and sometimes not.  The user I was working with when I wrote the question/problem last week has lost interest.  So I will have to wait until another volunteer arrives on the scene.

I need to disable/remove this question until then, but I don't know how.  The one time I tried to delete a question it turned into an involved, time consuming adventure.

Per user request in I have reduced the points in this question in preparation for its closure.

CS Moderator
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I know this question is being closed however I have had some experience with USR modems.

Set the hangup string to


Force-accepted on behalf of Asker, per

CS Moderator
houstonAuthor Commented:
>Closing questions normally is pretty easy -- you click on
>the button that says "Accept This Comment As Answer" and
>then grade it.

I don't think the Accept This Answer option is available unless someone has locked the question, and no one had.  If it is I missed it, and I apologize
Don't sweat it... It comes with the territory.

Welcome aboard...

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