[1] The Detroit–Columbia Central Office Building was commissioned by the Michigan Bell Telephone Company in 1927 at a cost of $1.2 million.

[2] The building was designed by Smith, Hinchman, & Grylls, and construction was completed in November 1928.

[3] The "dial system" office building, built to relieve the function of earlier "manual" exchanges, originally served around 7000 telephone customers in the central Woodward Avenue district of the city.

An identical panel also tops a slight recess located in the western bay to match the entryway.

[3] On the interior, the basement contains a cable vault, a battery room and the heating plant.