ADSL for video and data services

The asymmetric digital subscriber line (ADSL) draft standard was finalized as a standard by the ANSI in 1995, and commercial products are now available. As specified in this standard, ADSL technology will provide over a single twisted-pair loop a number of simplex channels (up to 6 Mb/s total capacity) from the central office to a subscriber and a number of duplex channels (up to 640 kb/s total capacity) while leaving the POTS service unaffected. Although the intention of the downstream data rates prescribed in the standard are to provide compressed video services, we believe a compelling case may also be made for data services over ADSL. This paper provides an overview of the ADSL standard, discusses video provisioning issues and how ADSL may compare to hybrid fiber-coax in this regard, and introduces a number of concepts for offering new data services using ADSL and existing LAN and WAN technology.