The Pentex Electronic Telephone Exchange

The Pentex System is designed for telephone exchanges in the range of 200 to 2000 lines. It uses reed-relay crosspoints in a 3-stage switching network; control operations are performed by semiconductor circuits and reed relays. The circuits are mounted on a new system of plug-in units. Easy growth in small increments, simple maintenance, low power consumption with standard exchange battery supplies, faulttolerance, and the ability to incorporate new features and services are main objectives achieved by the design.