To capture a session with PuTTY, open up PuTTY.

Look for Category Session -> Logging
 
Under Session Logging, choose “All session output” and key in your desired log filename (the default is putty.log).

This will create the file in the location you choose and begin logging everything from the session.

Issue the display techsupp, display log or other commands on the Digi unit.  The command results will be saved in the log file for analysis.