MacTerminal and Answerback message

[Info-Mac]

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From: info-mac@uw-beaver (info-mac)
Newsgroups: fa.info-mac
Subject: MacTerminal and Answerback message
Message-ID:
Date: Fri, 9-Nov-84 19:55:58 EST
Article-I.D.: uw-beave.2171
Posted: Fri Nov 9 19:55:58 1984
Date-Received: Mon, 12-Nov-84 10:55:32 EST
Sender: yenbut@uw-beave
Organization: U of Washington Computer Science
Lines: 32

From: Richard Garland
There was a question on the response MACTerminal gives to a host's
inquiry. There is a confusion here. There are 2 kinds of questions
that can be asked of the terminal, and 2 responses.

o The "Answerback message" is a remnant from teletype days
when systems would call up terminals (like news service
terminals) and ask for an ID. The system sends the ASCII
"ENQ" (-E) to get this response. On a VT100 you can
put this message in while in set up mode. It is generally
not used by time sharing systems. I usually put my Dept.
name in, since a thief probably wouldn't know how to reset
it (or invoke it). I only see it when I type some garbage
by mistake and by chance a ^E comes by and the terminal sends
back the ol' answerback message. It is also sent by a VT100
in response to a "long break" (SHIFT-BREAK on the VT100).

o The "Device Attributes" or "What are you". This identifies
the configuration of the terminal. For Old style (i.e. VT52)
DEC terminals it was invoked by "Z" to which a VT52 would
respond "/Z". For a VT100 it is invoked by the ANSI DA
(Device attributes) sequence "[c" or "[0c"" (the "0" is
optional). According to the VT100 User's Guide the terminaal
responds with the sequence "[?l;Psc" Where "Ps" is a number
between 0 and 7 giving what options are present (i.e. AVO, graphics
etc.) The sequence mentions in the question to this news group:
"[E;V" does not fit this pattern so either Macterminal
has its own ideas of ANSI sequences or the questioner may
have made a typo.

Rg
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