Principles and Systems for Power Supply of the Swedish Digital Telephone Network

The Swedish Telecommunications Administration - known in Sweden as Televerket - has one of the oldest telephone networks in the world. Advanced product development has enabled very high reliability values to be attained. It has therefore been possible to maintain costs and rates\´ at a low level. Changeover to digital technique will take place at an accelerated pace by replacement of older equipment. For technical reasons and from the subscribers\´ viewpoint, it has proved most appropriate for the introduction of the technique not to take place at the level of large exchanqes only, but more or less simultaneously at all levels in the network. The paper will outline the current state of development. It is also a follow-up and continuation of the Swedish contribution to "The state of the art" session at Intelec 1978.