Simulink Send / Receive data model Example

Built and attached example described in this link: http://www.mathworks.com/help/instrument/building-simulink-models-to-send-and-receive-data.html

Error Messages:

Error using serial/fopen (line 72) Open failed: Port: COM1 is not available. Available ports: COM9, COM15. Use INSTRFIND to determine if other instrument objects are connected to the requested device. Error using serial/fopen (line 72) Open failed: Port: COM1 is not available. Available ports: COM9, COM15. Use INSTRFIND to determine if other instrument objects are connected to the requested device. Error using serial/fprintf (line 144) Unexpected error: OBJ must be connected to the hardware with FOPEN..

Observations:

• same errors with attempt to perform exercise with COM2
• block settings only allow COM1-COM4, not COM9, COM15
• device manager show COM8, COM9 COM15 in use

Questions

• Why is COM1 unavailable? COM2?
• How to make COM1 'available'?

Diagnostic questions are good: actionable suggestions are appreciated. Examples are preferred. *Thank you*