The WCNN calls and 680 AM belong to the Dickey Family, They run Cumulus but do not own Cumulus* a public corporation yet. I guess, they could make a deal with themselves. Of course the deal could not be too sweet for the Dickey family because I am sure the Cumulus stock holders would sue. http://data.cnbc.com/quotes/CMLS/tab/8
They (Dickey) could probably license the calls to Cumulus for a dollar or something to keep it on the up and up.
But would Time Warner take issue with WCNN branding if the news product was not CNN's? I've often wondered how Time Warner has felt about 680 continuing to use the WCNN calls all these years, including the time when Cox was LMAing WCNN for all-news.
I think the MTM verses WKRP comes into play. Once the FCC issues Call letters, the station has to use them
at least for the station ID and has "full rights" to use the call letters of course the prior user of the calls (if there is one) might have some trade marks / intellectual properties and then lawyers get involved. Turner (Ted was running things back then) got out of the radio business and sold the NC TV station so they did not have a station to hold the call letters.
I'd forgotten about MTM vs "WKRP In Dallas, GA". I guess TWX wouldn't (couldn't) have an issue as long as Cumulus always used the calls in their entirety (no 'CNN like 'GST), didn't use the old original WCNN logo that contained the CNN logo, and didn't try to develop any branding that obviously played on the "CNN" part of the calls in any way (i.e., no "Cumulus News NOW!").
But on the other hand, since CNN is now out of radio, what if Cumulus licensed the CNN name and logo for its own news network, with a future WCNN-FM as the flagship?