VMS Help TCPIP Services, TELNET, Customizing  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    To customize the TELNET/TN3270 processing environment, issue
    ENABLE, DISABLE, and SET commands. You can modify how TELNET and
    TN3270:

    o  Send and receive transmissions

    o  Display processing on your terminal

    o  Interpret certain control characters

    You can redefine the following control characters, such as
    when your terminal or the remote host does not recognize the
    corresponding default control character.

    o  Echo

    o  Erase

    o  Escape

    o  Flush output

    o  Interrupt

    o  Kill

    o  Quit

    Use the SET command to redefine these characters. For example,
    the following command defines the interrupt character to be the
    letter a or A.

    TELNET> SET INTERRUPT "^a"

    TN3270 allows you to redefine your keyboard. You can redefine
    most IBM 3270 model functions and all emulated functions and
    characters. You can create a key definition file with DEFINE/KEY
    statements to redefine the keyboard. Or, you can redefine a key
    interactively, using the DEF KEY function (Ctrl/K on VT100- and
    VT200-series terminals).

    You can determine the mode TELNET uses to transmit data. The
    appropriate TELNET mode for a session depends on:

    o  The remote host to which you are connecting

    o  The applications you use

    The following table shows the modes that control TELNET
    communications.

    Mode              Function

    Local Characters  The local host interprets control characters,
    Mode              translating them in to TELNET protocol
                      sequences (ENABLE LOCAL_CHARS). Use this mode
                      when the local and remote hosts implement
                      different control characters. By default,
                      characters are interpreted by the remote host
                      (DISABLE LOCAL_CHARS).
    Binary Mode       The local host sends transmissions in binary
                      mode (ENABLE BINARY). Use this mode when the
                      remote host expects each line of data to end
                      with a carriage return/line feed combination.
                      By default, the local host sends transmissions
                      with the end-of-line character (EOL) mapped
                      to the carriage return/line feed combination
                      (DISABLE BINARY).
    Debug Mode        TELNET displays data flow in both hexadecimal
                      and readable text (ENABLE DEBUG). By default,
                      TELNET displays data in readable text only
                      (DISABLE DEBUG).
    Character         TELNET transmits data one character at a time
    Transmission      (SET MODE CHAR) rather than line-by-line. Use
    Mode              this mode when you run a text editor (on the
                      remote host) that does character processing.
                      Character transmission mode is the default.
    Line              TELNET transmits data one line at a time (SET
    Transmission      MODE LINE). Most clients send a character at a
    Mode              time. The remote host server must support line
                      transmission mode.

                      This allows you to do signal trapping as well
                      as local character editing and tab expansion.