Dbl - any one-suited hand
2C - Clubs and a higher suit
2D - Diamonds and a higher suit
2H - Hearts and Spades, no preference
2S - 6+ card Spade suit, weaker than Dbl then 2S.
For more information, go to www.bridgeguys.com or to an archived copy if you have previously saved that page to disk. (See BidBase help files for info about archiving bridge web pages.)
ACBL also has an article on DONT.
Doesn't Like Don't
The following was posted on rec.games.bridge by Gerben Dirksen:
The problem with DONT compared to Brozel is the 2C and the 2D bids. They come up more often but this makes a mess of things.
For example suppose partner bids 2C, showing Clubs and a higher suit. Fans of DONT will tell you this is a great bid since you got them out of 1NT and you show Clubs, so you may stop in 2C. Let's see what happens in practice.
(1NT) 2C (2H)
Now if you have Club support, that's great! If not, you will never ever ever find your fit if you have one. Partner might have Hearts. Or Spades or Diamonds. Oh well. Let's go one better: Third seat passes. That'll make things easier, right?
Suppose you have a quite normal distribution: 4S 2H 4D 3C. You are now in a 4 - 3 fit, possibly. Should you pass? Probably. Only to find out that the rest of the field played in a 4 - 4 fit in either pointed suit. But if you bid on, you will play 3C in the same 4 - 3 fit as before, now doubled as it turned out partner had Hearts.
2D has this same problem but less extreme as there are two suits to choose from.
My suggestion is to stick to what you have or if you want something new but similar, try "Lionel".