TN3270(1) UNIX Programmer's Manual TN3270(1)
tn3270 - full-screen remote login to IBM VM/CMS
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t
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\b0 sysname
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_
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\b0 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. _
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\b0 looks to the user in many respects like the Yale
ASCII Terminal Communication System II. _
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\b0 is actually
a modification of the Arpanet TELNET user interface (see
_
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\bt(1)) that interprets and generates raw 3270 control
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. _
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\b0 uses _
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\bs(3x) and the /_
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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,
/_
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\b0, (see _
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\b0(5)) or in an environment variable
_
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\bP_
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\b7_
\b0 (see _
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\bs_
\be_
\bt(1)). Any special function keys on the
ASCII keyboard are used whenever possible. If an entry for
the user's terminal is not found, _
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\b0 looks for an entry
for the terminal type u
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\bn.
\b. If this is not found, _
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\b0
uses a default keyboard mapping (see _
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\b7_
\b0(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, _
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\b0 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
If _
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\b7_
\b0 is invoked without specifying a remote host system
name, it enters local command mode, indicated by the prompt
``tn3270>''. In this mode, _
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\bn_
\b3_
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\b7_
\b0 accepts and executes the
open connect to a remote host
close close the current connection
status print connection status
Printed 7/9/88 January 11, 1986 1
TN3270(1) UNIX Programmer's Manual TN3270(1)
Other common _
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\bt commands are not available in _
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\b0.
_
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\b0 command mode may also be entered, after connecting to
a host, by typing a special escape character (typically
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.
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\bO
mset(1), telnet(1), termcap(3x), termcap(5), map3270(5),
_
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\be _
\bA_
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\bC_
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\bn _
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\bm _
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\br_
\bo_
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\bm
_
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\bt_
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\bn/_
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\bs _
\bM_
\ba_
\bn_
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\bl (IBM SB30-1911)
Performance is slow and uses system resources prodigiously.
Not all 3270 functions are supported, nor all Yale enhance-
Printed 7/9/88 January 11, 1986 2
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