It basically means the toilet needs a "closet bend" (90 turn) underneath it, on the same floor, to run the waste to the stack. No long vertical pipes (risers). That's how I understand it. (If I'm wrong, somebody will soon be along to correct me.)

This post was edited by homebound on Sun, Jun 22, 14 at 10:25

What are the distances allowed? Does the closet bend need to be immediately below the flange or can it go vertically 1ft, 2ft, 3ft before going horizontal? Then how far does it need to go horizontally before it can go vertical?

You need to hold it as tight as you can to the flange, to prevent the probably of siphoning the trap dry, leaving the sewer line open.

You are asking about the max. height allowed between the "closet flange" and "closet bend". It differs depending on what code, including the local variations, apply to you. It's somewhere between 2' to 3' vertical max., but you can look it up with those terms. Don't forget one needs to figure the maximum "horizontal" run permitted to reach the stack (with the proper drain slope, of course)