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Port Already Open / Modem Won't Hang Up

If you get a PORT ALREADY OPEN error when trying to establish a dial-up connection, that's Window's way of telling you some other device is using the modem.

If some other device is actually using the modem (such as a voice/fax program or you are already on a dial-up connection), the solution is to terminate the other task, or to disable auto-answer features in its software.

Sometimes, Windows gets confused, and it may seem like a reboot is the only answer. With Windows 95/98 in most cases, you can re-gain access to the port by terminating the rnaapp Task:

Press CONTROL, ALT & DELETE - this will bring up the Windows Task Bar Close Program box (Windows98SE shown at right)

Look for the Rnaapp task, select it, and then click End Task.


The procedure above may also be used as a last resort if you have difficulty getting your modem to hang up or disconnect a dial-up call.

The problem can also be caused by [prior] installation of AOL. See DUNS Error 602.


How do you disconnect? Depending upon the software (especially 3rd-party), the procedure used to disconnect a call may vary. When using Microsoft Windows DUNs, an icon will appear in your System Tray (normally part of the Start Bar at the bottom right of the screen) which will give you disconnect option when clicked. (right click, left click, double-click). Check to make sure you are using the correct procedure to disconnect your call. 

  Modem could be damaged. If your phone line is taken off-hook by the modem anytime it is powered on (the PC is on if internal), it is 'beyond repair'. Symptoms would include only being able to make the call if you plug the phone cord into the modem when you're ready to dial, or your line going 'dead' as long as the modem is plugged in. This can happen after a thunderstorm, and can also occur if your modem uses a newer all-electronic switch (proving to be somewhat less reliable than old electro-mechanical relay). Seek warranty replacement if applicable. Also see: Lightning Strikes.

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