Just to clarify before I go running off to Radio Shack, there are ways to communicate from an apartment building lobby to individual apartments via wireless systems? or at least using the existing electrical wiring.
The building had an old intercom system but it got old and squeaky. It was 'upgraded' to a system that uses the telephone lines. It requires that the building pay for two phone lines ($75 a month if you can believe it!)and only works if the telephone in the target apartment is not being used.
A wireless system would save money and be more convenient. Do you think there is something at Radio Shack that would work? Thanks!
If you are paying 75 bucks a month it's probably worth your trouble to buy a set of two and test it out.
http://www.radioshack.com/product/index.jsp?productId=2036287&cp=&kw=wireless+intercom&parentPage=search
There's a link to the product im talking about. It uses the AC Power for a carrier to all the electrical outlets. This is a 'Line Carrier' type device which will transmit the signal out to your transformer. It's only three channels though so whatever is heard on one is heard on all. No private conversations here.