FOR INFORMATION
April 6, 1998
NTT Releases Information on High-Speed Access System
Nippon Telegraph and Telephone Corporation (NTT) publicly released an outline of the
ATM-based Passive Double Star Optical Access System (ATM-PDS), a globally standardized
high-speed optical access network system, at the NTT Optical Communication Symposium on
April 8 and 9.
The system is based on high-speed access system technology proposed at a meeting of the
International Telecommunications Union's Telecommunications Study Group 15 in Geneva in
February. This proposal was based on specifications recommended by members of Full Service
Access Networks (FSAN), an association of carriers interested in the early installation
of optical access network systems. NTT submitted the proposal to the Group on behalf of the
FSAN members, who are confident that their proposal will lead to the early realization of
low-cost multimedia services.
Since access systems exist in various forms worldwide, equipment cannot be mass produced,
which leads to high costs, especially for installation. FSAN members are working to develop
a single standard that will help to lower costs through mass production.
The ATM-PDS access system integrates ATM and Passive Optical Network (PON) technology to
ransmit voice, data and video information as ATM cells over passive optical networks. An
Optical Line Termination (OLT) on the network side and an Optical Network Unit (ONU) on
the user's side are connected with optical splitters. The system transmission speed is 155
Mbps, so, for example, if each user requires 10Mbps, then 16 users can share one line card
because the OLT can be shared. The result is low-cost services at transmission speeds
required for multimedia.
NTT will continue to cooperate with other leading telecommunication corporations through the
FSAN to further develop standardized, high-speed optical access network access systems, as
well as related operation systems and services.
