1TN3270(1) General Commands Manual TN3270(1)
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6 tn3270 - full-screen remote login to IBM VM/CMS
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9 tn3270 sysname
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12 Tn3270 permits a full-screen, full-duplex connection from a VAX UNIX
13 machine to an IBM machine running VM/CMS giving the appearance of being
14 logged in directly to the remote machine on an IBM 3270 terminal. Of
15 course you must have an account on the machine to which you wish to
16 connect in order to log in. Tn3270 looks to the user in many respects
17 like the Yale ASCII Terminal Communication System II. Tn3270 is actu‐
18 ally a modification of the Arpanet TELNET user interface (see tel‐
19 net(1)) that interprets and generates raw 3270 control streams.
20 Emulation of the 3270 terminal is done in the Unix process. This emu‐
22 lation involves mapping 3270-style commands from the host into appro‐
23 priate sequences to control the user's terminal screen. Tn3270 uses
24 curses(3x) and the /etc/termcap file to do this. The emulation also
25 involves simulating the special 3270 keyboard keys (program function
26 keys, etc.) by mapping sequences of keystrokes from the ASCII keyboard
27 into appropriate 3270 control strings. This mapping is terminal depen‐
28 dent and is specified in a description file, /usr/share/misc/map3270,
29 (see map3270(5)) or in an environment variable MAP3270 (see mset(1)).
30 Any special function keys on the ASCII keyboard are used whenever pos‐
31 sible. If an entry for the user's terminal is not found, tn3270 looks
32 for an entry for the terminal type unknown. If this is not found,
33 tn3270 uses a default keyboard mapping (see map3270(5)).
34 The first character of each special keyboard mapping sequence is either
36 an ASCII escape (ESC), a control character, or an ASCII delete (DEL).
37 If the user types an unrecognized function key sequence, tn3270 sends
38 an ASCII bell (BEL), or a visual bell if defined in the user's termcap
39 entry, to the user's terminal and nothing is sent to the IBM host.
40 If tn3270 is invoked without specifying a remote host system name, it
42 enters local command mode, indicated by the prompt ``tn3270>''. In
43 this mode, tn3270 accepts and executes the following commands:
44 open connect to a remote host
46 close close the current connection
47 quit exit tn3270
48 z suspend tn3270
49 status print connection status
50 ? print help information
51 Other common telnet commands are not available in tn3270. Tn3270 com‐
53 mand mode may also be entered, after connecting to a host, by typing a
54 special escape character (typically control-C).
55 While in command mode, any host login session is still alive but tempo‐
57 rarily suspended. The host login session may be resumed by entering an
58 empty line (press the RETURN key) in response to the command prompt. A
59 session may be terminated by logging off the foreign host, or by typing
60 ``quit'' or ``close'' while in local command mode.
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63 /etc/termcap
64 /usr/share/misc/map3270
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67 Greg Minshall
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70 mset(1), telnet(1), termcap(3x), termcap(5), map3270(5), Yale ASCII
71 Terminal Communication System II Program Description/Operator's Manual
72 (IBM SB30-1911)
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75 Performance is slow and uses system resources prodigiously.
76 Not all 3270 functions are supported, nor all Yale enhancements.
784.3 Berkeley Distribution November 27, 1996 TN3270(1)