TN3270(1)						      General Commands Manual							 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 actually a modification of the Arpanet TELNET user interface (see telnet(1)) that  interprets	and  generates	raw  3270  control
       streams.

       Emulation  of the 3270 terminal is done in the Unix process.  This emulation 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 key-
       board  into  appropriate  3270  control	strings.   This  mapping  is  terminal	dependent  and	is  specified  in  a   description   file,
       /usr/share/misc/map3270, (see map3270(5)) or in an environment variable MAP3270 (see mset(1)).  Any special function keys on the ASCII key-
       board 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 command 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 temporarily 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
       typing ``quit'' or ``close'' while in local command mode.

FILES

       /etc/termcap
       /usr/share/misc/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					 November 27, 1996							 TN3270(1)