Door-mounted combination intercom and viewer

Claim 1

An improved combination intercom and viewer system for a door having an aperture therein, comprising: a pair of housings for engagement with respective sides of a door, each said housing having an aperture therein; a speaker and a microphone mounted in each said housing; a viewing tube insertable through said aperture in said door, said tube having opposite ends extending beyond said door sides and extending through said apertures in said housings; a two-way communication circuit mounted in one of said housings, said microphones and said speakers being selectively electrically connected to said two-way communications circuit, said circuit including first switch means for selectively establishing communication between said microphone in a preselected one of said housings and said speaker in the other of said housings; vibration damping material for isolating each said microphone from physical contact with its respective housing to prevent acoustic feedback caused by vibration, said two-way communication circuit further including a battery mounted in said same housing, said communication-circuit-containing-housing being an inside housing, the other said housing being an outside housing, first means cooperating with one of said tube ends for securing said outside housing to said door and second means for removably securing said inside housing to another of said tube ends whereby said inside housing is removable for servicing without removing or loosening said outside housing.