+This file describes what you must or might want to do to termcap entries
+to make terminals work properly and efficiently with Emacs. Information
+on likely problems with specific types of terminals appears at the end
+of the file.
+
+*** What you want in a terminal ***
+
+Vital
+1. Easy to compute suitable padding for.
+2. Never ever sends ^S/^Q unless you type them, at least in one mode.
+
+Nice for speed
+1. Supports insert/delete of multiple lines in one command.
+2. Same for multiple characters, though doing them one by
+one is usually fast enough except on emulators running on
+machines with bitmap screens.
+
+Nice for usability
+1. Considerably more than 24 lines.
+2. Meta key (shift-like key that controls the 0200 bit
+in every character you type).
+
+*** New termcap strings ***
+
+Emacs supports certain termcap strings that are not described in the
+4.2 manual but appear to be standard in system V. The one exception
+is `cS', which I invented.
+
+`AL' insert several lines. Takes one parameter, the number of
+ lines to be inserted. You specify how to send this parameter
+ using a %-construct, just like the cursor positions in the `cm'
+ string.
+
+`DL' delete several lines. One parameter.
+
+`IC' insert several characters. One parameter.
+
+`DC' delete several characters. One parameter.
+
+`rp' repeat a character. Takes two parameters, the character
+ to be repeated and the number of times to repeat it.
+ Most likely you will use `%.' for sending the character
+ to be repeated. Emacs interprets a padding spec with a *
+ as giving the amount of padding per repetition.
+
+ WARNING: Many terminals have a command to repeat the
+ *last character output* N times. This means that the character
+ will appear N+1 times in a row when the command argument is N.
+ However, the `rp' string's parameter is the total number of
+ times wanted, not one less. Therefore, such repeat commands
+ may be used in an `rp' string only if you use Emacs's special
+ termcap operator `%a-c\001' to subtract 1 from the repeat count
+ before substituting it into the string. It is probably safe
+ to use this even though the Unix termcap does not accept it
+ because programs other than Emacs probably won't look for `rp'
+ anyway.
+
+`cs' set scroll region. Takes two parameters, the vertical
+ positions of the first line to include in the scroll region
+ and the last line to include in the scroll region.
+ Both parameters are origin-zero. The effect of this
+ should be to cause a following insert-line or delete-line
+ not to move lines below the bottom of the scroll region.
+
+ This is not the same convention that Emacs version 16 used.
+ That is because I was led astray by unclear documentation
+ of the meaning of %i in termcap strings. Since the termcap
+ documentation for `cs' is also unclear, I had to deduce the
+ correct parameter conventions from what would make the VT-100's
+ `cs' string work properly. From an incorrect assumption about
+ %i, I reached an incorrect conclusion about `cs', but the result
+ worked correctly on the VT100 and ANSII terminals. In Emacs
+ version 17, both `cs' and %i work correctly.
+
+ The version 16 convention was to pass, for the second parameter,
+ the line number of the first line beyond the end of the
+ scroll region.
+
+`cS' set scroll region. Differs from `cs' in taking parameters
+ differently. There are four parameters:
+ 1. Total number of lines on the screen.
+ 2. Number of lines above desired scroll region.
+ 3. Number of lines below (outside of) desired scroll region.
+ 4. Total number of lines on the screen, like #1.
+ This is because an Ambassador needs the parameters like this.
+
+`cr', `do', `le'
+ Emacs will not attempt to use ^M, ^J or ^H for cursor motion
+ unless these capabilities are present and say to use those
+ characters.
+
+`km' Says the terminal has a Meta key.
+
+Defining these strings is important for getting maximum performance
+from your terminal.
+
+Make sure that the `ti' string sets all modes needed for editing
+in Emacs. For example, if your terminal has a mode that controls
+wrap at the end of the line, you must decide whether to specify
+the `am' flag in the termcap entry; whichever you decide, the `ti'
+string should contain commands to set the mode that way.
+(Emacs also sends the `vs' string after the `ti' string.
+You can put the mode-setting commands in either one of them.)
+
+*** Specific Terminal Types ***
+
+Watch out for termcap entries for Ann Arbor Ambassadors that
+give too little padding for clear-screen. 7.2 msec per line is right.
+These are the strings whose padding you probably should change:
+ :al=1*\E[L:dl=1*\E[M:cd=7.2*\E[J:cl=7.2*\E[H\E[J:
+I have sometimes seen `\E[2J' at the front of the `ti' string;
+this is a clear-screen, very slow, and it can cause you to get
+Control-s sent by the terminal at startup. I recommend removing
+the `\E[2J' from the `ti' string.
+The `ti' or `vs' strings also usually need stuff added to them, such as
+ \E[>33;52;54h\E[>30;37;38;39l
+You might want to add the following to the `te' or `ve' strings:
+ \E[>52l\E[>37h
+The following additional capabilities will improve performance:
+ :AL=1*\E[%dL:DL=1*\E[%dM:IC=4\E[%d@:DC=4\E[%dP:rp=1*%.\E[%a-c\001%db:
+If you find that the Meta key does not work, make sure that
+ :km:
+is present in the termcap entry.
+
+Watch out for termcap entries for VT100's that fail to specify
+the `sf' string, or that omit the padding needed for the `sf' and `sr'
+strings (2msec per line affected). What you need is
+ :sf=2*^J:sr=2*\EM:cs=\E[%i%d;%dr:
+
+The Concept-100 and Concept-108 have many modes that `ti' strings
+often fail to initialize. If you have problems on one of these
+terminals, that is probably the place to fix them. These terminals
+can support an `rp' string.
+
+Watch out on HP terminals for problems with standout disappearing on
+part of the mode line. These problems are due to the absence of
+:sg#0: which some HP terminals need.
+
+The vi55 is said to require `ip=2'.
+
+The Sun console should have these capabilities for good performance.
+ :AL=\E[%dL:DL=\E[%dM:IC=\E[%d@:DC=\E[%dP:
+
+The vt220 needs to be set to vt220 mode, 7 bit, space parity
+in order to work fully with TERM=vt220.
+
+If you are using a LAT terminal concentrator, you need to issue these
+commands to turn off flow control:
+
+ set port flow control disable
+ define port flow control disable
+
+On a PC, with terminal type AT386 or AT386-M, rumor has it that the termcap file
+that comes with the system has the `xt' capability, but should not have it.
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