ShowAllPorts

Used by network administrators, developers and even general users, port scanners have the role of identifying the open ports in a network. More often than not, the tools have a security role, as they help administrators identify vulnerable open ports malicious third parties could take advantage of.   
As the name suggests, ShowAllPorts is a tool designed to get a complete list of the serial ports on a Windows computer. According to the developer, the utility works with built-in ports, virtual ports and USB-to-RS-232 adapters.
The setup is a quick and uneventful operation that does not need any special attention on your part. The application comes with a clean single window interface that displays the ports, their details and whether they are currently available or busy. In case one is busy although you have nothing connected, then perhaps it is a matter worth investigating.
The list can be refreshed whenever a new device or service is launched with a click of a button. At the same time, the app allows users to add new ports. A further function worth mentioning is the one that shows the last port to be connected to the computer. This can come in handy for users who already have numerous ports installed.