Playing a tuneBefore you talk over some of the new Bell System long distance circuits, your operator presses keys like those shown above, one for each digit in the number of the telephone you are calling. Each key sends out a pair of tones, literally setting the number to music.
In the community you are calling, these tones activate the dial telephone system to give you the number you want.
It is as if the operator reached across the country and dialed the number for you.
This system, one of the newest developments of Bell Telephone Laboratories. is already in use on hundreds of long distance lines radiating from Chicago, Cleveland, New York, Oakland and Philadelphia, and between a number of other communities.
It will be extended steadily in other parts of the country - a growing example of the way Bell Telephone Laboratories are ever finding new ways to give you better, faster telephone service.
Playing a tune