This advertisement is from 1961. The text of the ad is reprinted below:

New for you—a more useful telephone number!

You may already have a telephone number like this. If you don’t, here’s how it will look.

The first three digits are your Area Code. They tell the telephone system what part of the country you live in. The next three digits designate your particular telephone office, and the last four pinpoint your particular phone.

It’s your phone number. Unique. Not another like it anywhere.

This new kind of number helps others reach you—and helps you reach others—faster.

Area Codes here now— All-Number Calling on the rise

Today the majority of our customers already dial their long distance calls directly by means of Area Codes. Eventually everyone will be able to. Until then, if you call through the Operator, you can save time by giving her the Area Code of the telephone you are calling when it is different from yours.

And already, in many parts of the country, letters have been replaced by numerals in telephone numbers. Before this change, we were running out of usable telephone numbers containing letters, while phones were steadily increasing. All-Number Calling, however, will give us enough numbers to meet our needs into the next century.

Telephone progress like this benefits everyone. Your new personal telephone number is another step in our effort to anticipate the needs of a growing America.

BELL TELEPHONE SYSTEM

All-Number Calling may permit you to use simple, tiny number-buttons on portable phones of the future.

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