He advised the Western Union to settle the case out of court and his advice was taken.
This great corporation war was concluded by a treaty (November 10, 1879) in which the Western Union acknowledged that Bell was the inventor, that his patents were valid, and agreed to retire from the telephone business.

The Bell Company, on its part, agreed to buy the Western Union Telephone System, to pay the Western Union a royalty of twenty per cent on all telephone rentals, and not to engage in the telegraph business.
Had this case been decided against the Bell Company it is almost certain that the telephone would have been smothered in the interest of the telegraph and its development delayed for many years.
Soon after the settlement of the Western Union suit, the original group which had created the telephone withdrew from the scene.

Bell went back to teaching deaf-mutes.

He has since busied himself with the study of airplanes and wireless, and has invented an instrument for transmitting sound by light.

The new telephone company offered him $10,000 a year as chief inventor, but he replied that he could not invent to order.