Bell House

From www.si.edu:

Located at the corner of 35th Street and Volta Place, N.W., Bell House, erected in 1853, was purchased in 1881 by then Smithsonian Regent Alexander Graham Bell for his father. Bell maintained a laboratory in the carriage house behind the main house in which he conducted experiments focussing on gaining advances for the hearing impaired. In 1988 Bell House was acquired by the Denver-based telecommunications company US WEST as a Washington base for corporate Chairman Jack MacAllister.