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From: drake@drake.almaden.ibm.com
Newsgroups: comp.protocols.ibm
Subject: Re: 3270 ATTN key -- what does it generate?
Message-ID: <374@rufus.UUCP>
Date: 18 Dec 90 00:28:11 GMT
References: <1990Dec15.014654.28204@naitc.naitc.com> <4467@lib.tmc.edu>
Sender: news@rufus.UUCP
Organization: IBM Almaden Research Center
Lines: 17

The ATTN key is, as was already mentioned, an out-of-band communications key.
It's the moral equivalent of the "escape" key in many telnet implementations;
you hit the escape key (often ctl-t) and the telnet client prompts you to
enter various commands.  When the command completes you're put back into your
telnet session.

ATTN is used similarly to allow 3270s to exit their host session and talk to
the network.  This allows users to forcibly log off from hosts (a la ctl-t Q)
and other such things.  

Since ATTN's used to talk to the network (VTAM, the 3x74 et al), not the host,
I'm not sure how you'd implement it on a telnet server.


Sam Drake / IBM Almaden Research Center 
Internet:  drake@ibm.com            BITNET:  DRAKE at ALMADEN
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