If your APC Smart UPS has been placed in Smart Mode, prior to starting Windows NT 4.0, it is possible that the Windows NT boot time configuration and detection code, sent to the COM port, may be interpreted as a Calibration.
This will not happen if your boot.ini file contains the /NOSERIALMICE:COMn switch.
At a CMD prompt, type:
attrib -r -s -h c:\boot.ini
Edit c:\boot.ini and add the /NOSERIALMICE:COMn switch. Example:
multi(0)disk(0)rdisk(0)partition(1)\WINNT="Windows NT" /NOSERIALMICE:COM1 multi(0)disk(0)rdisk(0)partition(1)\WINNT="Windows NT \[VGA mode\]" /basevideo /sos /NOSERIALMICE:COM1The above example assumes that the UPS is connected via COM 1.