ADSL Comes of Age

Asymmetric digital subscriber line (ADSL) is a technology invented by BellCore in the mid-1980s as a method to offer video and voice over the same copper loop. The intent was to offer VoD to their customers when they wanted it. When the technology fizzled out because VoD failed to take off and typical deployment of ADSL was too slow to run any real-time video over it; however, the technology seems to have been forgotten for almost a decade.

ADSL had a renewed interest from phone companies again after their voice network became overloaded with data. ADSL was being looked at again, but this time the main application that was driving it was data—not video like it was originally designed for. In the early 1990s, phone companies wanted to offer DSL as a method to prevent data from overtaking their voice network but there was a problem. There’s no DSL standard, and phone companies don’t make the equipment themselves. Southwestern Bell, Bell Atlantic, and BellSouth got together to form the Joint Procurement Contract (JPC) to search for an ADSL equipment maker. They picked Alcatel as the main supplier of their Digital Subscriber Line Access Multiplexers (DSLAMs) and customer premises equipment (CPE). US West chose not to participate in the consortium and instead picked a startup company called NetSpeed (later acquired by Cisco). Bell Atlantic went with Westell as the main supplier for their DSL equipment. Other competitive local exchange carriers (CLECs) such as Northpoint Kovad, Rhythms, and Cincinnati Bell all offered DSL services later on— each choosing ADSL equipment from different vendors.