Quatech RS-232 - Manual (Page 22)

Figure 9 --- Device Manager Advanced Port Settings
9. Use the Logical COM Port names to access the serial ports on your
ESC(LP)-100 through your software applications. Note: The
Logical COM Port name is assigned to your ports by Windows .
This name is required by a Windows application when accessing a
particular port.
ESC(LP)-100 User's Manual 16