Intercom Central GROUND wire Power-line 3 CHANNELS Intercom System, Two Stations Set.

hi this is video number three in a series of videos about nutone apartment house entry intercom system specifically the model 478 or what's called the system for intercom system if you haven't watched video number one and video number two I suggest you do so they give you good overviews video number one shows how the most basic of 478 systems are wired video number two shows how a to entry building with two entrance directories would be wired and this is the first video in basic problem solving for common problems with entry intercom system so what we have here on the whiteboard is a very simplified drawing of a very simplified system to not make it overly complicated I have paired it down to the bare minimum for today's problem one of the most common calls that we get about apartment house intercom problems are the tenant in the building cannot speak with the people at the entrance the