4.3BSD - /usr/man/cat1/tn3270.0

TN3270(1)                                                            TN3270(1)


NAME
       tn3270 - full-screen remote login to IBM VM/CMS

SYNOPSIS
       tn3270 sysname

DESCRIPTION
       Tn3270  permits  a  full-screen, full-duplex connection from a VAX UNIX
       machine to an IBM machine running VM/CMS giving the appearance of being
       logged  in  directly to the remote machine on an IBM 3270 terminal.  Of
       course you must have an account on the machine to  which  you  wish  to
       connect  in order to log in.  Tn3270 looks to the user in many respects
       like the Yale ASCII Terminal Communication System II.  Tn3270 is  actu‐
       ally  a  modification  of  the  Arpanet TELNET user interface (see tel���
       net(1)) that interprets and generates raw 3270 control streams.

       Emulation of the 3270 terminal is done in the Unix process.  This  emu‐
       lation  involves  mapping 3270-style commands from the host into appro‐
       priate sequences to control the user’s terminal  screen.   Tn3270  uses
       curses(3x)  and  the  /etc/termcap file to do this.  The emulation also
       involves simulating the special 3270 keyboard  keys  (program  function
       keys, etc.)  by mapping sequences of keystrokes from the ASCII keyboard
       into appropriate 3270 control strings.  This mapping is terminal depen‐
       dent  and  is  specified  in  a  description  file,  /etc/map3270, (see
       map3270(5)) or in an environment variable MAP3270 (see  mset(1)).   Any
       special function keys on the ASCII keyboard are used whenever possible.
       If an entry for the user’s terminal is not found, tn3270 looks  for  an
       entry for the terminal type unknown.  If this is not found, tn3270 uses
       a default keyboard mapping (see map3270(5)).

       The first character of each special keyboard mapping sequence is either
       an  ASCII  escape (ESC), a control character, or an ASCII delete (DEL).
       If the user types an unrecognized function key sequence,  tn3270  sends
       an  ASCII bell (BEL), or a visual bell if defined in the user’s termcap
       entry, to the user’s terminal and nothing is sent to the IBM host.

       If tn3270 is invoked without specifying a remote host system  name,  it
       enters  local  command  mode,  indicated by the prompt ‘‘tn3270>’’.  In
       this mode, tn3270 accepts and executes the following commands:

            open      connect to a remote host
            close     close the current connection
            quit      exit tn3270
            z         suspend tn3270
            status    print connection status
            ?         print help information

       Other common telnet commands are not available in tn3270.  Tn3270  com‐
       mand  mode may also be entered, after connecting to a host, by typing a
       special escape character (typically control-C).

       While in command mode, any host login session is still alive  but  tem‐
       porarily  suspended.  The host login session may be resumed by entering
       an empty line (press the RETURN key) in response to the command prompt.
       A session may be terminated by logging off the foreign host, or by typ‐
       ing ‘‘quit’’ or ‘‘close’’ while in local command mode.

FILES
       /etc/termcap
       /etc/map3270

AUTHOR
       Greg Minshall

SEE ALSO
       mset(1), telnet(1), termcap(3x),  termcap(5),  map3270(5),  Yale  ASCII
       Terminal  Communication System II Program Description/Operator���s Manual
       (IBM SB30-1911)

BUGS
       Performance is slow and uses system resources prodigiously.

       Not all 3270 functions are supported, nor all Yale enhancements.


4.3 Berkeley Distribution      January 11, 1986                      TN3270(1)