23 Oct
2009
23 Oct
'09
9:10 p.m.
I'm struggling trying to create an accurate telnet client with ANSI
emulation. The basic codes are easy enough and well documented, but
there are a lot of obscure codes to do things like 'set terminal mode'
to 'vertical editing mode' which I can't find good descriptions for.
I can't even figure out if a pure ANSI terminal supports wrapping to the
next line when you hit the edge of the screen, or if that is controlled
by an escape sequence. To further confuse things, a lot of people lump
the DEC terminals in with discussions of ANSI terminals, and although
they are close they are not the same. DEC extended a lot of things.
I've been googling, reading source code, and experimenting. It's slow
and painful.
Does anybody have a good reference they would recommend?
Thanks,
Mike
23 Oct
23 Oct
9:55 p.m.
On 23 Oct 2009 at 23:10, Michael B. Brutman wrote:
I'm struggling trying to create an accurate telnet client with ANSI
emulation. The basic codes are easy enough and well documented, but
there are a lot of obscure codes to do things like 'set terminal mode'
to 'vertical editing mode' which I can't find good descriptions for.
Do you mean that you want a standard? ECMA-48's a good one:
http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-
048.pdf
Welcome to the wonderful world of headaches. My memory of the
stuff (NAPLPS and Videotex) was that it was harder to interpret the
standards than it was to write the code.
Good Luck,
-Chuck
25 Oct
25 Oct
11:01 a.m.
Ok - here is a nice, specific question ..
This chart can be found at http://vt100.net/docs/tp83/appendixb.html .
It shows the codes generated for the arrow keys.
Cursor Key Codes Generated
ANSI Character Generated
Cursor Reset(Cursor) Set (Application)
Up ESC [ A ESC O A
Down ESC [ B ESC O B
Right ESC [ C ESC O C
Left ESC [ D ESC O D
There are two columned - one for RESET and one for SET. In my nice
simple universe, I press a key and a series of codes gets sent to the
host machine. So what does it mean to Reset or Set in this context?
I think I want to use the first column, but what does the second column
mean?
Thanks,
Mike
1:54 p.m.
On 25 Oct 2009 at 13:01, Michael B. Brutman wrote:
There are two columned - one for RESET and one for
SET. In my nice
simple universe, I press a key and a series of codes gets sent to the
host machine. So what does it mean to Reset or Set in this context?
In the the case of the VT100 (which probably is the one you're
probably interested in), keypad application mode is entered with
esc [?1h (i.e. "set")
and exited with
esc [?1l (note the lowercase "L"; i.e. "reset")
The reason for the names is that in "reset" mode, the cursor keypad
generates cursor movement commands. Also note that the keypad may
be put into numeric mode with "esc >" .
--Chuck
5:12 p.m.
Chuck Guzis wrote:
On 25 Oct 2009 at 13:01, Michael B. Brutman wrote:
Hi Chuck,
Just a little more help because I'm being super thick - what exactly
does "keypad application mode mean"? I understand the difference
between numeric mode and non-numeric, or I'm assuming that it works the
same way it does on PC. But the "application mode" thing is throwing me
off because I don't know what it means and can't draw my own analogies.
Mike
There are two columned - one for RESET and one
for SET. In my nice
simple universe, I press a key and a series of codes gets sent to the
host machine. So what does it mean to Reset or Set in this context?
In the the case of the VT100 (which probably is the one you're
probably interested in), keypad application mode is entered with
esc [?1h (i.e. "set")
and exited with
esc [?1l (note the lowercase "L"; i.e. "reset")
The reason for the names is that in "reset" mode, the cursor keypad
generates cursor movement commands. Also note that the keypad may
be put into numeric mode with "esc >" .
--Chuck
9:52 p.m.
On 25 Oct 2009 at 19:12, Michael B. Brutman wrote:
Just a little more help because I'm being super
thick - what exactly
does "keypad application mode mean"? I understand the difference
between numeric mode and non-numeric, or I'm assuming that it works
the same way it does on PC. But the "application mode" thing is
throwing me off because I don't know what it means and can't draw my
own analogies.
The VT100 User Guide is pretty awful with its language. I like the
VT220 or even the TVI 922 manuals better for clear language.
Okay, let's start with the cursor keys (up down right left). In VT52
mode, these generate ESC A, ESC B, etc. In VT100 mode, the default
is to generate ESC [ A, ESC [ B and so on. These correspond to the
ANSI control seuqnences that move the cursor one position.
There is another mode, called "application" mode. The cursor keys
generate ESC O A, ESC O B, etc.
One puts the cursor keys into "application mode" with ESC [ ? 1 h.
One put s the cursor keys into "normal" mode with ESC [ ? 1 l.
(lowercase "L"). Why are these called "set" and "reset"?
Easy--the
ANSI seuqence "ESC [ ? (some number or string of numbers) h" is the
ANSI "set mode" (mnemonic SM) command. The other one is the ANSI
"reset mode" (mnemonic RM) command.
Okay, now for the numeric keypad.
These also can generate either what's printed on the keycaps (hex 39
for 9) or a unique code that distinguishes them from the keys with
the same labels on main section of the keyboard. This is called
"application mode" also--but it's separate from the cursor keys.
To enter application mode for the numeric keypad use "ESC ="; to
return to numeric mode, use "ESC >". These are not ANSI commands,
but are DEC's own contribution to the VT100--but most implementations
follow them anyway.
Note that there are many DEC-specific VT100 commands, such as
enabling double-wide and double-wide, double-high characters.
Hope this helps,
Chuck
26 Oct
26 Oct
12:47 p.m.
cctalk-bounces at classiccmp.org wrote:
Just a little more help because I'm being super thick - what exactly
does "keypad application mode mean"? I understand the difference
between numeric mode and non-numeric, or I'm assuming that it
works the
same way it does on PC. But the "application mode" thing is throwing
me off because I don't know what it means and can't draw my own
analogies.
iirc that ANSI standard was based on the DEC VT100, so if you read the
VT100 user manual (available on Manx I think) you'll have a good idea of
what everything is supposed to do.
My recollection is that in numeric keypad mode you cannot tell the
difference between "1" on the keypad and "1" above the "Q".
In "application keypad" mode, "1" on the keypad generates an escape
sequence.
Antonio
2:19 p.m.
On 26 Oct 2009 at 19:47, arcarlini at iee.org wrote:
iirc that ANSI standard was based on the DEC VT100, so
if you read the
VT100 user manual (available on Manx I think) you'll have a good idea
of what everything is supposed to do.
Other way 'round, I think. The original applicable ANSI standard is
X3.41-1974, which defines the simpler escape sequences. The VT100
wasn't introduced until 1978.
Additional sequences for alternate character sets were defined by
X3.64-1979.
Both standards underwent revisions as the years went on, but neither
standard is currently active, being supplanted by ISO 2022 and 6429,
respectively.
FWIW, well into the 1980's, the ANSI escape sequences were mostly
ignored by the industry (DEC being an exception). Hence the
evolution of TERMCAP and CURSES.
--Chuck
28 Oct
28 Oct
2:02 p.m.
arcarlini at iee.org wrote:
cctalk-bounces at classiccmp.org wrote:
I took a good stare at the VT220 Programmers Reference. It looks like
'application mode' isn't that special. It really looks very similar to
the way the keypad is handled on the PC - in one mode you get the
numbers on the keypad, and in the other mode you get an ESC string to
indicate special keys.
Have I finally got this right? :-)
Mike
Just a little more help because I'm being
super thick - what exactly
does "keypad application mode mean"? I understand the difference
between numeric mode and non-numeric, or I'm assuming that it
works the
same way it does on PC. But the "application mode" thing is throwing
me off because I don't know what it means and can't draw my own
analogies.
iirc that ANSI standard was based on the DEC VT100, so if you read the
VT100 user manual (available on Manx I think) you'll have a good idea of
what everything is supposed to do.
My recollection is that in numeric keypad mode you cannot tell the
difference between "1" on the keypad and "1" above the
"Q".
In "application keypad" mode, "1" on the keypad generates an escape
sequence.
Antonio
5534
days inactive
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days old
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