In 1908, AT&T President Theodore Vail made a transcontinental telephone line the company’s top priority, even though he knew that the technology to build one did not exist. The next year, Chief Engineer John J. Carty raised the stakes when he announced in San Francisco that AT&T would have a transcontinental line open in time for the 1915 exposition the city planned to mark the completion of the Panama Canal.

Wanted: Breakthrough

What AT&T needed was a scientific breakthrough, a way to amplify an electrical signal. Carty did two things. He hired a young physicist, Dr. Harold Arnold, to study the question. And he spread the word in the scientific and electrical engineering community that AT&T would pay handsomely for an electrical amplifying device.

On Oct. 30, 1912, independent inventor Dr. Lee de Forest brought his invention, the audion or three-element vacuum tube, to AT&T’s engineering department. It provided a small amount of amplification before the system broke down, with the audion emitting a bright blue haze. Arnold recognized almost immediately that the blue haze was caused by ionization of the residual gasses in the tube. If he increased the vacuum, thereby removing most of the residual gasses, the audion would become a practical amplifier.

Installing amplifiers

On Arnold’s recommendation, AT&T bought the patent rights from de Forest. By summer 1913, AT&T had tested high-vacuum tubes on the long distance network. By fall, the company had begun constructing the line west from Denver, and upgrading the line to the east. On June 17, 1914, AT&T completed the line, erecting the last pole at Wendover, Utah.

Erection of final pole, completing construction of the first continental telephone line. Wendover, Utah, June 17, 1914.

There was only one problem: AT&T had completed the line before the Panama-Pacific exposition was ready. So the company waited, and on Jan. 25, 1915, opened the line with great fanfare and celebrations.

The first call

Alexander Graham Bell (center) and several AT&T executives prepare to inaugurate transcontinental telephone service, January 25, 1915.

Four locations participated in the first call. Alexander Graham Bell, inventor of the telephone and co-founder of AT&T, led a group of dignitaries in New York. His one-time assistant Thomas Watson, led a group in San Francisco. AT&T President Theodore Vail spoke from Jekyll Island, Ga. And U.S. President Woodrow Wilson spoke from the White House.

At one point during the call, someone asked Professor Bell if he would repeat the first words he ever said over the telephone. He obliged, picking up the phone and repeating “Mr. Watson, come here, I want you.” To which Watson, in San Francisco, replied, “It would take me a week now.”