Most radio stations have something called an RDS, or Radio Data System, that embeds information in the signal like the station name, programming features and song information.  Most of today's vehicles have RDS built into them to display that text.  But earlier this week, some public radio stations were displaying a vulgar message that was not sent by the stations.

Hackers were able to infiltrate the coded signal and send a message of their own that slammed the host of their noon show, Fresh Air with Terry Gross.  Michigan Radio is a public radio network owned by the University of Michigan.  While one report was unclear on what the message said, one subscriber to the Michigan Radio & TV Buzzboard posted  a picture of their radio as it displayed the hacked message.

"Terry Gross has a small penis" was displayed on WFUM 91.1 in Flint, and another affiliate in Western Michigan.  Michigan Radio took immediate action upon realizing the hacking had taken place, including changing the system's passwords, and posting a letter of apology to its listeners.  While officials still don't know who hacked the signal, they are working with the U of M's IT department to trace the source.

It's unclear if the above message was the only one sent.