info-mac@uw-beaver (info-mac) (11/10/84)
From: Richard Garland <OC.GARLAND%CU20B@COLUMBIA.ARPA> 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" (<CTRL>-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 "<ESC>Z" to which a VT52 would respond "<ESC>/Z". For a VT100 it is invoked by the ANSI DA (Device attributes) sequence "<ESC>[c" or "<ESC>[0c"" (the "0" is optional). According to the VT100 User's Guide the terminaal responds with the sequence "<ESC>[?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: "<ESC>[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 -------