Info needed on "proper" vt-100 emulation...

Info needed on "proper" vt-100 emulation...

Post by John Gogg » Thu, 28 Dec 1995 04:00:00



Ok, I know that this often just causes arguments, but I'm hoping someone
can help me here.  Here's the situation:  I have a software package
(sorry, but it'll have to remain nameless for now due to some contract
stuff :) that states it supports "VT100 emulation."  Now, I have tried
several different TCP/IP telnet clients in VT100 emulation mode
(including "telnet" equivalents by FTP Software, Microsoft, and Novell).  
In all of these, "F5" does not come out properly -- the software I am
using at the other end does not see F5, but sinstead gets some garbage.  
If I remember correctly, the true DEC VT100 terminal does not even have
an F5 key, does it?  I believe that is why the confusion the problems
like this occured -- because different vendors implemented "F5"
different, correct?

In any case, an argument has now developed over this situation.  I am
tending to argue that since the "F5" codes from Novell, Microsoft, and
FTP software seem to match each other -- that THEY are doing what is
proper.  On the other hand, the software vendor is arguing that they went
with what was the "most common definition of F5" that they found -- and
therefore, it is Novell, MS, and FTP (among others) that are wrong -- and
that if they cannot be re-mapped, then we'll have to buy a different
front-end telnet client to use.  (Of course, they won't even tell us
their recommended telnet client -- they don't have one -- which makes it
real convienent for them, eh?)

So -- basically, my question is this: is there a written "standard"
anywhere for the key definitions for "VT100 emulation"?  Or is it simply
a moot point because the original/true DEC VT100 terminals did not do
"F5" (or something like that)?

Any/all ideas/suggestions welcome...  Thanks!

 - John...

 
 
 

Info needed on "proper" vt-100 emulation...

Post by Tim Shop » Thu, 28 Dec 1995 04:00:00




>Ok, I know that this often just causes arguments, but I'm hoping someone
>can help me here.  Here's the situation:  I have a software package
>(sorry, but it'll have to remain nameless for now due to some contract
>stuff :) that states it supports "VT100 emulation."

As an aside, if you do need good VT100 emulation on a PC-type
platform, I can heartily recommend either MS-DOS Kermit or
Kermit 95.  These even come with a tool that put Gold (aka PF1)
where God intended it to be!

Quote:>  Now, I have tried
>several different TCP/IP telnet clients in VT100 emulation mode
>(including "telnet" equivalents by FTP Software, Microsoft, and Novell).  
>In all of these, "F5" does not come out properly -- the software I am
>using at the other end does not see F5, but sinstead gets some garbage.  
>If I remember correctly, the true DEC VT100 terminal does not even have
>an F5 key, does it?

Right.  I'm typing this on a true VT100 at this very moment, as
a matter of fact.

Quote:>  I believe that is why the confusion the problems
>like this occured -- because different vendors implemented "F5"
>different, correct?

I would argue that a good VT100 emulator should send nothing
at all if F5 is pressed.  Numerous problems have developed
with the widespread availability of "enhanced" VT100 emulators -
resulting in many software packages that cannot be used from
true VT100's!

Quote:>In any case, an argument has now developed over this situation.  I am
>tending to argue that since the "F5" codes from Novell, Microsoft, and
>FTP software seem to match each other -- that THEY are doing what is
>proper.  On the other hand, the software vendor is arguing that they went
>with what was the "most common definition of F5" that they found -- and
>therefore, it is Novell, MS, and FTP (among others) that are wrong -- and
>that if they cannot be re-mapped, then we'll have to buy a different
>front-end telnet client to use.  (Of course, they won't even tell us
>their recommended telnet client -- they don't have one -- which makes it
>real convienent for them, eh?)

>So -- basically, my question is this: is there a written "standard"
>anywhere for the key definitions for "VT100 emulation"?  Or is it simply
>a moot point because the original/true DEC VT100 terminals did not do
>"F5" (or something like that)?

It is a moot point.  There is no VT100 F5 key, so there can be no
standard F5.  Technically, it doesn't even have F1-F4; instead it has
PF1-PF4 on the numeric pad.  If you want more function
keys, go to a good VT220 or VT320 emulator.  Otherwise you're tying
yourself into a specific terminal emulator.  Unfortunately, this
is all too common a problem today...
If I had a dollar for every application I
have that supposedly worked with "VT100" terminals but actually
only works with one specific enhanced emulation of a "VT100"
I'd be rich.

For some good information about terminals and emulators, use
anonymous ftp to cs.utk.edu, and look in /pub/shuford/terminal.
Even better, find someone with a real VT100 manual and only
use what's in there.  Best of all, get a real VT100 and test
your application using that.  I've got a few dozen in
my garage (with manuals... hint,hint.)



 
 
 

Info needed on "proper" vt-100 emulation...

Post by Bob Sch » Thu, 28 Dec 1995 04:00:00


Quote:>So -- basically, my question is this: is there a written "standard"
>anywhere for the key definitions for "VT100 emulation"?  Or is it simply
>a moot point because the original/true DEC VT100 terminals did not do
>"F5" (or something like that)?

     I doubt there is a written "standard" for VT100 emulation.  The VT100
keyboard is NOT the same as the IBM PC 101-key keyboard.  For one thing, there
are no Fnn function keys.  Second, the keypad has 18 keys, whereas the PC has
17.  There is no "alt" key, though there is a "ctrl" key.  Finally, while
there are four arrow keys, I don't think the six keys that, on the PC, live
above the arrow keys are found on the VT100 (they came out with the VT200
series).

     The main problem with VT-100 emulation is how to deal with the "missing"
keypad key.  On the VT-100, the top row of keys are the four function keys
PF1, PF2, PF3, and PF4.  The next row has four keys, 7, 8, 9, and "-"; the
next row of keys is 4, 5, 6, and ",";  then comes 1, 2, 3, and a double-high
"Enter", and finally a double-wide 0 and ".".  There is no "+" key.

     Some emulations blow off the top row of the PC's keys and substitute
F1-F4 for PF1-PF4.  Others try to stay with the "feel" of the VT100, using the
top PC row as PF1-PF4.  Of course, this means trapping NumLock and treating it
in a special manner ...

Bob Schor
RT-11/TSX+ User/Abuser

 
 
 

Info needed on "proper" vt-100 emulation...

Post by Stephen Hoffm » Thu, 28 Dec 1995 04:00:00


:Ok, I know that this often just causes arguments, but I'm hoping someone
:can help me here.  Here's the situation:  I have a software package
:(sorry, but it'll have to remain nameless for now due to some contract
:stuff :) that states it supports "VT100 emulation."  Now, I have tried
:several different TCP/IP telnet clients in VT100 emulation mode
:(including "telnet" equivalents by FTP Software, Microsoft, and Novell).  
:In all of these, "F5" does not come out properly -- the software I am
:using at the other end does not see F5, but sinstead gets some garbage.  
:If I remember correctly, the true DEC VT100 terminal does not even have
:an F5 key, does it?  I believe that is why the confusion the problems
:like this occured -- because different vendors implemented "F5"
:different, correct?
:
:In any case, an argument has now developed over this situation.  I am
:tending to argue that since the "F5" codes from Novell, Microsoft, and
:FTP software seem to match each other -- that THEY are doing what is
:proper.  On the other hand, the software vendor is arguing that they went
:with what was the "most common definition of F5" that they found -- and
:therefore, it is Novell, MS, and FTP (among others) that are wrong -- and
:that if they cannot be re-mapped, then we'll have to buy a different
:front-end telnet client to use.  (Of course, they won't even tell us
:their recommended telnet client -- they don't have one -- which makes it
:real convienent for them, eh?)
:
:So -- basically, my question is this: is there a written "standard"
:anywhere for the key definitions for "VT100 emulation"?  Or is it simply
:a moot point because the original/true DEC VT100 terminals did not do
:"F5" (or something like that)?

  There is no <F5> key on the VT100, so the whole argument is (IMNSHO)
  entirely moot.

  On a Digital VT-series terminal or terminal emulator, the <F5> key is
  one of the keys that does not (by default) send an ASCII character or
  ANSI character sequence from the terminal to the host on the VT200-series
  and later terminals.  Under device-specific circumstances, the <F5> key
  can be used to (deliberately) generate a framing error -- a deliberately-
  generated framing error is usually called a <BREAK> -- on the serial line.

  In addition to the <BREAK>, there _is_ an ANSI-defined <F5> keyboard
  sequence, and some terminals and terminal emulators have chosen to allow
  it to be (optionally) sent to the host.  (The Digital VT420 is one such
  terminal -- one can set <F5> to send the <F5> sequence ("<esc>[15~")
  function key sequence, to send a <BREAK>, or one can disable it and use
  it as a "decoration" key -- using the VT420 keyboard set-up screen.)

  If the emulator has decided to send something when <F5> is pressed, then
  it is (at least in this area) a superset of the Digital VT100.  When <F5>
  is pressed, if the emulator chooses (by default) to send something to the
  host that is not the defined <F5> sequence ("<esc>[15~") nor the <BREAK>,
  then the emulator implementation is (in my opinion) incorrect.

        --

  Here are the part numbers for the VT100 documentation.  Note that there
  were several different variations of the VT100 -- some had the Advanced
  Video Option (AVO), and there were various other options available for
  the terminal that could be stuffed into the VT100 expansion card cage.

        EK-VT100-RC   VT100 PROGRAM REFERENCE CARD
        EK-VT100-TM   VT100 TECHNICAL MANUAL
        EK-VT100-UG   VT100 USERS GUIDE

  The VT101 had fewer options:

        EK-VT101-RC   VT101 PROGRAMMING REFERENCE CARD
        EK-VT101-TM   VT101 SERIES TECHNICAL MANUAL
        EK-VT101-UG   VT101 VIDEO TERMINAL USERS GUIDE

  The VT500-series is a rather more recent terminal:

        EK-VT520-RM   VT520/VT525 PROGRAMMERS INFO

        --

  The above is *my* opinion.  ("Mine! Mine! All Mine!"  :-)
  The "official" opinion of Digital Equipment Corporation may differ.

  ------------------------------ Opinionative -------------------------------

                       reachable via the weird-wide web
  ---------------------------------------------------------------------------

 
 
 

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