There's about 7,284 different ways to interpret the definition of a VT100/VT220/ANSI termianl, and no two programmers ever pick the same interpretation. The termcap used to compile the terminfo files for Linux has a lot of errors and omissions as well.

For this reason I use KoalaTerm for emulation on Windows workstations. It costs $35/pop, but it gives me the flexibility I need to get the function keys to work, and once it's set up it stays that way.

I always install my own terminfo file to go with it too. Remember, Linux uses SVr4 terminfo, so modifying the termcap does nothing until you compile it into a terminfo definition and put it in the right directory.

The other way is Wyse60, but that means expensive terminal emulation programs. American small and medium business has traditionally run 100% on Wyse60, but programmers of low cost emulation are uninterested - Wyse60 isn't used in the universities.

I've talked to several publishers of VT100/200 emulation and they are all completely, totally, 220% uninterested in serving customer needs. All they want to do is produce yet another "BEST" VT220 emulator, and it'll it'll have a different interpretation of how a VT220 works than any of the others.

. . most of the rest of us are not connected to "the very definition of VT220". Linux in particular has ratty termcap/terminfo definitions that need to be fixed before use.

My favorite item is that the lower function keys use completely different coding than the higher function keys, and whether the transition is at F4 or F5 or whatever seems a matter of opinion, but some programmers use one or the other encoding all the way through. Which one appears also to be a matter of opinion.

Anyway, next time I mess with this stuff I'll take a look at PuTTY and see what I think of it. By the way, KoalaTerm makes full use of available TrueType fonts, which many emulators do not.