It's a funny hybrid system. A sequence of chords take the place of a simple strike on a gong or a bell. The sequence will pick up wherever it left off, so the psuedo-song varies from hour to hour. The company called it a "chime strike" which seems appropriate; it's more than a simple strike, but not exactly a tune (chime) either.
I think the chords make a pleasing tone and a very interesting strike.