Phone number rings apartment buzzer? why?

Question

A couple of months ago we were switching phone companies and phone numbers... so we wanted to check if our new # worked... so we called from the cell phone to the new phone number (in the same room we were checking it) and it rang some guys apartment unit buzzer... we hung up and tried a couple more times... the guy said he lived in an apartment building a block or two away. if distance has anything to do with it... we carried the convo on like it was phone to phone... weird... does anybody know why this happened? Also it got fixed within an hour.

Answer 1

Some phone companies provide a service that is a door buzzer system for apartment buildings.  It is old technology.  Basically there would be a box at the apartment building that you dialed the person's apartment number and their phone would ring and they could buzz you in.  The system was linked back to the phone companies office in some cases to provide the service.  It is old and not used much anymore, so there could be lines running from an apartment building back to the phone company that are not even used for that anymore, but until the line is needed for a spare, it may stay connected, or your line got crossed up with the other guys line.  Which can happen and does happen.

So when you called your line, it rang at his apartment and it was just a coincidence that his apartment still used the phone company provided door buzzer service, so a call to him if it was on the right line would look like a call from his door buzzer at the front door.  

I'd say it was a 1 in a million thing if not rarer than that.