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From: nadji@uscvax.UUCP (Behzad Nadji)
Newsgroups: net.info-terms
Subject: terminal emulators and invalid ESC sequence
Message-ID: <171@uscvax.UUCP>
Date: Sat, 28-Dec-85 14:39:24 EST
Article-I.D.: uscvax.171
Posted: Sat Dec 28 14:39:24 1985
Date-Received: Sun, 29-Dec-85 20:20:22 EST
Distribution: net
Organization: CS&CE Depts, U.S.C., Los Angeles, CA
Lines: 17

What is a terminal emulator supposed to do when it receives an 
invalid escape sequence. For example, what should a VT52 emulator 
do when it receives an <Esc>M or <Esc>X ?

  1- Ignore the sequence.
  2- Write it to screen as it is.
  3- Ignore the sequence, but indicate an error (by a beep or by writing a
                 block (?) character to screen).
  4- Write it to screen as it is, but indicate an error as above.
  5- others?

Choices 3 and 4 sound awful; 1 is ok but may cause problems if the actual 
text being received contains the <Esc> character. My choice has been 2 but 
I was wondering if anyone knows what the standard is. 

                              ARPA:     nadji%usc-cse@csnet-relay.arpa
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