SOUTHWESTERN BELL MAIN DIAL BUILDING
The Southwestern Bell Telephone Company built the first two-stories of the Main Dial Building at 424 South Detroit Avenue in 1924 to house the switchboards and operators needed to make telephone connections for the new dial equipment introduced to Tulsa. The original building was in the Gothic Style of architecture. The first floor has arched windows that are framed with terra cotta.
In 1930, the company added four stories to the original structure to house divisional offices. The later addition was in the Zigzag Art Deco style, designed by J. R. Timlin. The new façade featured vertical stepped-back panels in brick, and ornamentation in terra cotta. The colors and types of material used on the additional floors carefully matched the colors of the original lower ones, thus helping to marry the classical Gothic style with the more modern Art Deco.