How to make a breakaway telephone

Props: One of the trick props we needed for The Book of Grace was a phone which John Doman smashed during every performance. We decided that the phone receiver would remain real, but the part it hung on would be cast from plaster. It would all hang on a wooden base, and a collection of “phone innards” will be held inside the plaster part, so when it broke, an assortment of metal bells, chip-boards, and other electronic components would be left hanging on the wall.