A Distributed Power Architecture for the Digital Switching System in NTT

Nippon Telegraph & Telephone Corporation (NTT) is now studying reliability design in the face of possible disruption due to failure of the Integrated Service Digital Network (ISDN). In relation to this, efforts are being made to improve power supply system reliability. As the digital switching system plays a particularly important part in ISDN, intensive research has concentrated on the power supply system it uses. This paper describes the distributed power architecture for the D70 switching system developed for local or combined local and toll stages. Emphasis on this subject is important because failure in the local switching system directly affects users. This power supply system is effective for reducing the scale of communications problems which occur due to power equipment failure. As a result, large-scale service disruption vulnerability of communications equipment which possess greater capacity and more centralized functions can be reduced by the use of this system.