Article View: comp.protocols.ibm
Article #795Re: 3270 ATTN key -- what does it generate?
From: Jon Lewis
Date: Tue, 18 Dec 1990 20:30
Date: Tue, 18 Dec 1990 20:30
29 lines
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1549 bytes
I'll add some info as to what the ATTN key does when pressed on a real 3270.
I can't speak about tn3270, as I know nothing about that product.
Keyboard 3274 VTAM
ATTN key pressed
DFC Signal ---->>>>>
When convenient,
send change direction
(CDI). This turns
the line around, and
allows the 3270 to
enter data.
Note, that it is up to the application/presentation services layer on the
IBM side to handle the DFC (Data Flow Control) command and turn the line
around. For LU2(3270), when a signal is received, the application
should complete any pending I/O, e.g. if it is the middle of a chain, and
turn the line around as soon as possible.
Hope this helps, if not, and you want some more clarification, drop me
some email.
Jon Karl Lewis
Information Networks Division - Hewlett Packard Company
jkl@hpindzl.cup.hp.com
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Path: arc1-ca.pugleaf.net!utzoo!attcan!utgpu!watserv1!watmath!att!linac!uwm.edu!spool2.mu.edu!sdd.hp.com!zaphod.mps.ohio-state.edu!samsung!dali.cs.montana.edu!milton!uw-beaver!Teknowledge.COM!unix!hplabs!hpda!hpcupt1!hpindwa!jkl From: jkl@hpindwa.cup.hp.com (Jon Lewis) Newsgroups: comp.protocols.ibm Subject: Re: 3270 ATTN key -- what does it generate? Message-ID: <39290006@hpindwa.cup.hp.com> Date: 18 Dec 90 20:30:13 GMT References: <9012162110.AA17045@lilac.berkeley.edu> Organization: Hewlett-Packard, Cupertino CA Lines: 29