System Design for Small to Medium PABX Equipment

Small to medium PABX systems are standardized in Germany according to their power characteristics with the designation "Baustufe 2". They are designed for between 30 and 180 extensions. On the one hand these systems are manufactured in relatively large quantities, on the other hand they are - due to the attractiveness of this market - under considerable cost pressure. The power supply is of great importance, not only in regard to the technology but above all in regard to the hardware cost. 10 - 15 % of the total cost is quite realistic for the power supply. Consequently the design of such a power supply is not only a technical problem but above all the problem of combining the best of the technical and economical features.