Communications: Telephone nets go digital: Digital communication links promise flexible, economical telephone services for both home and office

While digital information plays an ever larger role in today's economy, anyone transmitting digital data from one place to another faces a number of obstacles. A residential user with, say, a home computer terminal is limited to transmitting or receiving at a rate at or below the 4-kilohertz bandwidth allowed by analog telephone lines. As a result, services requiring higher band-widths, such as single-frame video, are out of reach for such users. Businesses can get special, high-capacity hookups for various purposes, but every time their requirements change, new circuits must be installed, often at considerable expense.