2) Five digit dialing in some areas not well populated or served by
> community dial offices?
Having lived in a town where an ESS was being installed, forcing
7-digit dialing, I asked a friend who worked for the then Bell Labs why an ESS couldn't be programmed to retain 5 digits. His response was that the opposite problem was more of a concern, i.e. allowing for 7 and 10 digit local dialing, giving as an example the situation in Silicon Valley at the time, where the 415 and 408 area codes were across the street from each other.