This sounds like you have an incorrect cable setup between the K3S/P3 and the computer.
You have a USB cable between the computer and the K3S, and that has created port COM3. You also appear to have a USB-to-serial adapter between the computer and the P3, which has created port COM8. You also mentioned COM5, but that appears to be for something else (a rotor controller, a Winkeyer, a KPA500, or some other device) that doesn't enter into the picture.
Take a look at the P3 manual, revision H1, pages 5 and 6. If you want to use the K3S's USB connection for rig control (that's COM3), then to get the P3 to work correctly you must have a CBLP3Y connected between the K3S and both RS232 connectors on the P3, as on page 5. Your software (K3 Utility, Commander or any other rig control software) must use COM3. In the K3S, CONFIG:RS232 is set to USB with this cable connection. The COM8 cable is not connected to the P3 and doesn't do anything for you in this setup; you can use it to control some other device if you want.
If your cable setup is like the one on page 6 of the manual, then you must set the K3S's CONFIG:RS232 to 38400 and use COM8 for rig control. Your software must use COM8; COM3 is not used in this setup.
Whichever setup you settle upon (using COM3 with a CBLP3Y, or using COM8 with a connection between the computer and the P3), only one program can use the serial port at a time.
---In Elecraft_K3@..., <kenw817821@...> wrote :
I have k3 utility, latest version 18.104.22.168.
Computer Device manager says I have com ports of 3,5,8.
K3s has line from USB port to my computer, it is COM 3.
This is confimed when I unplug the line and COM3 disappears from the ports list.
I must set K3s RS232 to be 38400 for P3 to work properly.
It does not display correctly when K3s RS232 is set to USB.
DX Labs commander wants to use Port 8.
When I try to use the K3 Utility, it will not use 3,5,or 8
unless I turn DXLABS commander off, then it uses port 8.
If I SET K3s RS232 to be USB the utility also will work,
using port 3.
So to use the Utility, I have to do a work around.
Is this normal?