I have a Dell Optiplex 7020 running Windows 10 with one physical serial port. I checked the device manager and found that it only detects one COM port (COM1), while in other machine running windows XP/7/8 I would see up to 7 or more available COM ports (COM2,COM3...,COM7) :

device manager screenshoot

I also check via powershell :

power shell screenshot

I would like to connect another device with a serial interface but the problem is the COM1 is already being used, while I cant find another COM ports.

Is it the limitation on the machine and/or windows 10? Is there a way to manually add another COM ports (COM2,COM3,..COM7) to my machine ?

  • Connect your device to the serial port and assign it COM1 in whatever configuration, terminal emulator, etc. you use and it should work just fine.... Use COM1 just as shown in the two screen shots. You are seeing the Port of the Serial which correctly has COM1 assigned to it. If there is nothing connected to the serial port, just plug in and configure accordingly away.... – Pimp Juice IT Jan 5 '17 at 4:52
  • does it mean that the machine only have 1 COM? can I add COM port manually? – caesardo Jan 5 '17 at 6:34
  • I believe that it means that your machine only has the one serial port to assign a COM port to, so yes essentially it'll mean that. You might have a quick read over COM (hardware interface) and note where it states... " It might refer not only to physical ports, but also to virtual ports, such as ports created by Bluetooth or USB-to-serial adapters." and "As of 2007, most computers ship with one or no physical COM ports" – Pimp Juice IT Jan 5 '17 at 12:53

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