After graduation from Yale in 1899, de Forest entered the new field of communications using the wireless telegraph which had earlier been introduced by Marconi. He searched for a better detector, or receiver, and patented a device called a “responder.” It was faster than the Marconi coherer.

He formed a wireless telegraph company and teamed with Abe White, a stock promoter of dubious reputation. The company, while successful, ran afoul of the law, and de Forest resigned as its president: In a November 28, 1906 letter from de Forest on American De Forest Wireless Telegraph Company letterhead, he writes “Gentlemen, I herewith tender my resignation as vice president and as director of the American de Forest Wireless telegraph Company, the same to take effect immediately.” On the carbon copy saved in the de Forest papers he added to the formal typed letter in his own hand, “This is the funeral of my first born child! This is the finis to the hopes and efforts which has made up my strenuous life for the first five years. That which I had wrought with the fair and ceaseless endeavor to make grand and lasting and triumphant is frustrated, sand-bagged, throttled and despoiled by the robber who has fattened off my brains. But my work goes on while I live.”