The model 302 is built upon a rectangular steel base plate on which are mounted the ringer unit, the induction coil, a metal can containing two capacitors, and a connector terminal plate. The base was supported by four felt- or leather-covered triangular feet attached under each corner. The housing sat atop the base, secured with screws, and contained the rotary dial and the hook switch, which was activated with two plunger rods in the handset cradle by removing or replacing the handset.