I've got a full bath rough-in in the concrete slab in our basement. I'm confused about the bathtub drain connection. The stub for the tub drain protrudes through the concrete. There's no "box" around the drain (recessed into the concrete). Am I supposed to purchase a tub designed for above-floor installation (like the American Standard Princeton model)? Or am I missing something basic here?

You should have a box around the drain, something like 6 inches side to side and about 12 inches front to back. Sometimes they will put the box in just below the grade of the finished floor and you might have to preak out a thin layer of concrete to expose it.

Is this drain about 2 inches from the plate that the water pipes are in and about 14 inches form the wall on the side of the tub. I am assuming that the walls are already there. If not I think you will understand what I mean.

Let me know hwat you have.

I'm confused about the bathtub drain connection. The stub for the tub drain protrudes through the concrete. There's no "box" around the drain (recessed into the concrete).
If the cement's solid and not just a thin coating you were left with a rough in for a shower. Having said that.
If the raiser's 1 1/2" from the front plate and 15 1/2" from the back wall this may still be a tub rough in.
Give me the measures and I'll tell you what you have. Regards, Tom

There were no walls framed in when we bought the house. This 2" PVC pipe stub is 18.5" from the closest concrete (foundation) wall. The next closest concrete wall is 63.5" away. Allowing for a 2x4 stud wall (up against the existing concrete), it seems like a natural drain location for a RHD tub. I'll try to post a picture of the layout I envision.

I assume that the lack of the box means that this drain is intended for a tiled shower floor. A tub would be much more useful for our family. Will a special tub designed for above-floor installation will work in this instance.

I think I'm uploading a jpg along with this post.

The way you have it drasn up and if the drain is at the end of the tub like you show it I am sure it was plumbed for a tub. Therefore if I were you I would break out concrete around the drain so that you could install a waist and overflow below the concrete, actually you want the shoe part of the waste and overflow to be level with the concrete floor. So measure how far the hole in the bottom of the tub is going to be away from the wall and make you hole just a couple of inches bigger than that.