Keyspan USA-19 - Manual (Page 30)

Next, select COM1 or COM2 depending on which port you wish to emulate. Please note which
port you select as you will be selecting this port in your serial device's software later.
Now that you've selected COM1 or COM2, you will need to map the VirtualPC COM port to a
Keyspan MAC serial port. This is what causes data to be sent to COM1 or COM2 to be sent to
to your Keyspan serial port. To do this, turn on the Mac serial port radio button and select your
Keyspan:USB Serial Adapter for Mac OS X-v2.x User Manual
This User Manual applies to the Keyspan USB Serial Adapter Software for Mac OS X.
Rev 05jul15 Page 30