In 1922, McGraw entered the telecommunications business with the purchase of Central Telephone and Electric Company of St. Louis, Missouri.

[1][2] Through a series of mergers, acquisitions, purchases, sales, and re-purchases, the electrical supply and manufacturing side of the business would form the nucleus of McGraw-Edison.

Its largest coverage areas by lines installed were Las Vegas, Chicago suburbs (Des Plaines, Park Ridge and unincorporated Cook County just outside the village limits of Northbrook, Glenview and Niles), Tallahassee, FL and Charlottesville, VA.

Centel also owned a stake in Keyfax, a teletext/videotex service operating in the Chicago area, alongside Honeywell and Field Enterprises.

Ultimately, Sprint did not end up keeping either of Centel's businesses (cellular and local telephone service) that it acquired.