To keep a log of your TELNET session, use the /LOG_FILE
    qualifier. (You cannot use this qualifier with a TN3270 session.)

    The following example establishes a TELNET connection to node
    central, sets the terminal type to VT200, and logs all session
    output to the file CENT.LOG in your current directory.

    $ TELNET/LOG_FILE=CENT.LOG/TERMINAL_TYPE=VT200 CENTRAL