UPS + com1 port connection problem

[CaptainHaplo]

Couple of possibilities. Kaleun gave you a good one. Another is remember that Com 1 is often assigned by the Bios as the serial port on the MB. Most current MB's dont have a serial connection built on anymore, but the bios still has the settings so it assignes the resources even if the device isn't present.

Often people try to get around this issue if they need a com port by using a usb to serial adapter - but when you do - they usually default install to com 5 or above. If your using one of these, make sure you disable the com1 assign in Bios, then set the adapter to be com1.

The next thing - Microsoft in their wisdom decided that if you set your system to go into standby or hibernate - when it wakes back up - it does NOT wake the serial port. Make sure you reboot your PC before attempting to use com1 - as it might simply still be "asleep". This can and oftend does cause anything using com 1 - to fail. Sometimes an app calling com1 will wake the port back up - but that is kind of a random it may or may not thing.