Types of toilets
There are really 2 main types of toilets we have and use. They are a P trap toilet and S trap toilet and now days a concealed toilet which is and or a combination of p and s trap. P trap toilets go through a wall or to the side when installed where the S Trap goes through the floor when installed.
P Trap Toilet-
As you can see from the picture P trap toilets has the waste pipe connection coming straight from out the back of the toilet pan. Depending where the install is they are designed to go through a wall and bring the waste pipe out to connect to the sewer. Used on houses where there is no access to under the floor or sub floor access. Easier to install for a DIY and are mainly used on external walls.
S Trap Toilet-
As you can see from the picture the S trap waste pipe connection goes down at the back of the pan. This type of toilet pan is mainly suited and used on houses that have the waste pipe to go through the floor and out to where it connects to the sewer drain.