ASCII graphics in X terminal programs

Asked this in /b/ but I'm not that naive enough to think I'll get a real answer there.

So I want to play Nethack in a windowed shell with its fancified ASCII, rather than simple ASCII characters.

It looks fine when I play Nethack in text mode and not in X... but something's up. It could be the terminal program, but it happens with ALL terminal programs I've tried on my system so far. It could be Nethack, or it could be some wonky terminal settings.

How do I got extended ASCII showing up normally in xterm/Konsole/etc?

Can't post a screenshot of what it looks like in these here text boards... but uh, it just looks like a garbled Nethack dungeon.

>>1
omg U baka use decgrafix not imbgraaffix ok ne?  also gfet real font liek dejavu olls

ps you can maybe get nethax0r workin by setting encoding to same as windoze with imbgrafix ok ne?  dec suerior thouge becuz it used A_ALT sumthin for lines and they are really lkjhxzqw loplplpol