


TN3270(1)	    UNIX Programmer's Manual		TN3270(1)



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

SYNOPSIS
     tn3270 sysname

DESCRIPTION
     _T_n_3_2_7_0 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.  _T_n_3_2_7_0 looks to the user in many respects like the Yale
     ASCII Terminal Communication System II.  _T_n_3_2_7_0 is actually
     a modification of the Arpanet TELNET user interface (see
     _t_e_l_n_e_t(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 appropriate sequences to control the user's termi-
     nal screen.  _T_n_3_2_7_0 uses _c_u_r_s_e_s(3x) and the /_e_t_c/_t_e_r_m_c_a_p
     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
     dependent and is specified in a description file,
     /_u_s_r/_s_h_a_r_e/_m_i_s_c/_m_a_p_3_2_7_0, (see _m_a_p_3_2_7_0(5)) or in an environ-
     ment variable _M_A_P_3_2_7_0 (see _m_s_e_t(1)).  Any special function
     keys on the ASCII keyboard are used whenever possible.  If
     an entry for the user's terminal is not found, _t_n_3_2_7_0 looks
     for an entry for the terminal type unknown. If this is not
     found, _t_n_3_2_7_0 uses a default keyboard mapping (see
     _m_a_p_3_2_7_0(5)).

     The first character of each special keyboard mapping
     sequence is either an ASCII escape (ESC), a control charac-
     ter, or an ASCII delete (DEL).  If the user types an
     unrecognized function key sequence, _t_n_3_2_7_0 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 _t_n_3_2_7_0 is invoked without specifying a remote host system
     name, it enters local command mode, indicated by the prompt
     ``tn3270>''.  In this mode, _t_n_3_2_7_0 accepts and executes the
     following commands:

	  open	    connect to a remote host
	  close     close the current connection
	  quit	    exit tn3270
	  z	    suspend tn3270



Printed 11/26/99	November 27, 1996			1






TN3270(1)	    UNIX Programmer's Manual		TN3270(1)



	  status    print connection status
	  ?	    print help information

     Other common _t_e_l_n_e_t commands are not available in _t_n_3_2_7_0.
     _T_n_3_2_7_0 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),
     _Y_a_l_e _A_S_C_I_I _T_e_r_m_i_n_a_l _C_o_m_m_u_n_i_c_a_t_i_o_n _S_y_s_t_e_m _I_I _P_r_o_g_r_a_m
     _D_e_s_c_r_i_p_t_i_o_n/_O_p_e_r_a_t_o_r'_s _M_a_n_u_a_l (IBM SB30-1911)

BUGS
     Performance is slow and uses system resources prodigiously.

     Not all 3270 functions are supported, nor all Yale enhance-
     ments.























Printed 11/26/99	November 27, 1996			2



