Otto B. Blackwell
Otto Bernard Blackwell (August 21, 1884 – November 21, 1970) was an American electrical engineer known for his pioneer contributions to the art of telephone transmission.Mr. Blackwell held about two dozen patents in the telephone field.Edwin H. Colpitts and Otto B. Blackwell published an important paper on carrier multiplex telephony and telegraphy in the Transactions of the AIEE in 1921.They summarized work on bandpass filters and vacuum-tube electronics, which had enabled a four-channel commercial system to be placed in operation between Baltimore, MD, and Pittsburgh, PA, in 1918.He became vice president of Bell Laboratories, and at retirement in 1949 he was an assistant vice president at American Telephone and Telegraph the parent company.