I thought "28 inch" is a term sometimes used for 700c, in some parts of the world. I could be mistaken, though. The key to the tires being interchangeable, besides staying within broad width limitations, is the bead seat diameter of the tires/rims. 700c is 622mm bead seat diameter. Inner tubes are another matter. For example, 27 inch tires (630mm bead seat diameter) and 700c tires, again staying within reasonable width limitations, can use the same sized inner tubes-