In 1969, the FCC enacted its "one-to-a-market" rule, which prohibited common ownership of AM radio and television stations with overlapping coverage areas under certain conditions while grandfathering some already existing instances. Avco's ownership of WLWC, WLWT, WLWD, and WLW radio (a 50,000-watt, clear-channel station which can also be heard throughout much of eastern North America at night) was granted protection under the clause. But as a condition of maintaining three television stations with common coverage areas Crosley/Avco operated WLWC, WLWT, and WLWD with shorter transmission towers. In 1975, Avco announced the sale of its broadcasting outlets; channel 4 was sold in February 1976 to the Providence, Rhode Island-based Outlet Company, who then changed the station's call letters to the current WCMH-TV. The call letters were selected to match the ATA airport code for Port Columbus International Airport, "CMH".