Telephones and telegraphs: 1902 : [and Municipal electric fire alarm and police patrol systems] (1906)
United States. Bureau of the Census, Steuart, William Mott, 1861-, Martin, Thomas Commerford, 1856-1924, Abbott, Arthur Vaughan, 1854-, Mayer, William · Washington : Govt. Print. Off. · leaf 78
CENTRAL AUTOMATIC EXCHANGE, GRAND RAPIDS, MICHIGAN, 6,000 LINE FULL AUTOMATIC. … MAIN EXCHANGE PITTSBURG, PENNSYLVANIA, BEFORE OCCUPANCY BY OPERATORS. CENTRAL OFFICE OR EXCHANGE. 45 cent of the total number of boards; but there were345 telephones per switchboard for the Bell com-panies, while the average for boards of independentcompanies was 141. The Bell system showed…
Telephone · Telegraph · Fire alarms
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