[John W. O'Leary, Pres. of the U.S. Chamber of Commerce, talking on new telephone line with John W. Spangler, Pres. of the Seattle Chamber of Commerce]

The invention of the telephone still remains a confusing morass of claims and counterclaims, which were not clarified by the huge mass of lawsuits to resolve the patent claims of commercial competitors. The Bell and Edison patents, however, dominated telephone technology and were upheld by court decisions in the United States. Bell has most often been credited as the inventor of the first practical telephone. Alexander Graham Bell was the first to patent the telephone as an "apparatus for transmitting vocal or other sounds telegraphically". The telephone exchange was an idea of the Hungarian engineer Tivadar Puskás (1844 - 1893) in 1876, while he was working for Thomas Edison on a telegraph exchange. Before the invention of the telephone switchboard, pairs of telephones were connected directly with each other, practically functioned as an intercom. Although telephones devices were in use before the invention of the telephone exchange, their success and economical operation would have been impossible with the schema and structure of the contemporary telegraph systems. A telephone exchange was operated manually by operators, or automatically by machine switching. It interconnects individual phone lines to make calls between them. The first commercial telephone exchange was opened at New Haven, Connecticut, with 21 subscribers on 28 January 1878, in a storefront of the Boardman Building in New Haven, Connecticut. George W. Coy designed and built the world's first switchboard for commercial use. The District Telephone Company of New Haven went into operation with only twenty-one subscribers, who paid $1.50 per month, a one-night price for a room in a city-center hotel. Coy was inspired by Alexander Graham Bell's lecture at the Skiff Opera House in New Haven on 27 April 1877. In Bell's lecture, during which a three-way telephone connection with Hartford and Middletown, Connecticut, was demonstrated, he first discussed the idea of a telephone exchange for the conduct of business and trade.

During the administrations of Presidents Wilson, Harding, Coolidge, and Hoover, the National Photo Company supplied photographs of current news events in Washington, D.C., as a daily service to its subscribers. It also prepared sets of pictures on popular subjects and undertook special photographic assignments for local businesses and government agencies. The bulk of the images were created between 1909 and 1932. The photographic files of the National Photo Company, including an estimated 80,000 images (photographic prints and corresponding glass negatives), were acquired by the Library from its proprietor Herbert E. French in 1947.