from apartments vacation or other condominiums hotel rooms mobile homes motorhomes houses etc the inside and outside electrical intercom units 10 11 are shown in the present drawings as being mounted on the free left vertical edge as viewed from the inside of the dwelling space 15 of door 14 for doors that pivot the other way by which it is meant that the hinges are on the left side as viewed from the inside of the dwelling space and the free edge is on the right it is merely necessary to invert both the inside and outside units 10 11 and mount them at the right edge of the door inside unit 10 has a rectangular housing 18 formed of two mated portions or sections 19 20 that are secured together by screws not shown the housing portions or sections 19 20 are injection molded of synthetic resin similarly outside unit 11 has an injection molded synthetic resin rectangular housing 21 formed of mated portions or sections 22 23 held together by unshown screws the housing 21 of the outside unit is substantially smaller than is that of the inside unit the outside unit preferably contains no electronics or moving parts and represents only a small fraction of the manufacturing cost of the through door intercom system preferably the housing 21 of outside unit 11 has four feet or pads 24 at corner regions thereof and adapted to seat on the outside surface 25 of door 14 correspondingly there are provided at corner regions of inside housing 18 four feet or pads 26 that rest on the inside door surface 27 pads 24 and 26 are formed of.