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Port Already Open

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by techworker

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How to change Com port from "busy -1" to "busy 0" so as to free it up from a "Port Already Open" status. Nothing connected to Com1 port. No applications can be specifically seen accessing Com1 port. Search of Registry does not find any reference to Com1 or Serial0 being set to busy. With Com1 port in "Port Already Open" status it cannot be used.

5 replies

by techworker

I do believe that the auto-answer feature is a function of communications software that would be associated with a modem or other communications device. In this case, there is no modem attached to the port or communications software accessing the port. Somehow the port status for Com1 got changed to "Busy -1" and that makes the port appear to be "Open" or in use. Also, this is a Windows 2000 Professional OS environment - forgot to mention that before.

by cactus pete

Something running on the box is listening on that com, or that's where a device is working. It's more likely to be software...

Close programs, disable services, etc until you find out which is grabbing it.

A good trick is to identify everything running a process in the task manager.

by techworker

Prior to posting the question all startup items where removed from the startup folder, all processes that could be shut down where shut down, WinFax was removed from the system and cleaned from the Registry, and the problem is still wlith us. System diagnostics show that Com1 is working, but Open. Problem is, can't identify what process or application is accessing the port if any.

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