7D rotary exchanges in Rumania

The design of the 7D system as installed in Rumania follows the general principle of the 7A rotary system. The chief innovations are the use of single-motion switches throughout and the introduction of partial combined line finder and finals. The distinctive features are: (1) reduction in floor space; (2) uniformity of equipment due to single-motion switches; (3) increased flexibility of outlets for selection; (4) increased facilities for miscellaneous services; (5) automatic routining testing scheme; (6) introduction of overflow arrangements; (7) simplified alarm scheme; (8) extended service observing facilities; (9) direct reading traffic recording; (10) universal register. All these points are considered in detail in the paper.