Improved detached-contact circuit drawing

THE ever-increasing complexity of telephone and telegraph switching circuitry in the Bell System had reached a stage about 10 years ago, where many of the conventional type of schematic circuit drawings presented difficulties in training of personnel and maintenance. It then became necessary, particularly for the more complex circuits, to prepare and maintain a separate series of drawings—especially streamlined for training purposes and for aiding maintenance. However, the preparation of two sets of drawings for these cases and keeping them in step as improvements and changes were added was costly.