EA4TX RemoteBox Series Hardware Reference & Operational Manual page 30

The Drivers are included in the enclosed CD-ROM. Select "Search removable
media (floppy, CD-ROM,..), and then click "Next".
Once installed Windows will automatically create a Virtual COM port to
communicate with the RemoteBox.
A Virtual COM port is the simulation of a serial port in software in order to allow
a USB port to take its place. Virtual serial ports are necessary to enable an application
that was written for the serial port to run on a computer that does not have that
interface. Once the driver is installed, the RemoteBox device will always connect to
the appropriate Virtual COM Port to communicate with the computer and the RBM
software.
Page 30
Hardware Reference and Operational Manual: RemoteBox