Abstract: A method of making an acoustic transducer for telephones consists of securing the magnet assembly and the armature supporting ring inside the plastic casing of the transducer and then surrounding or partly surrounding these with a thermosetting resin such as epoxy resin, poured inside the casing.The core, the armature supporting ring and the outer edge of the casing are then machined with reference to the magnet face to the required very small tolerances, the cured resin holding the parts securely during the machining operations.

Abstract: The invention enables individual buttons to be replaced on a push-button telephone without disturbing the other buttons.Each button is retained in position by lugs formed on the lower portion of the button which engage underneath the edges of a hole formed in the body of the telephone. The edges of the hole are provided with slots and by sliding the button until the lugs become aligned with the slots, the button can be removed. A cover or escutcheon plate fits over the buttons to prevent inadvertent sliding and consequent removal of the buttons.