RealityChuck speak’um truth: until about 1970, it was bells on the truck. I think the microchip hit the scene about then and I’m sure it was invented strictly to go on IC trucks and annoy the populace at large.
Yes, that’s true! This was just a lucky guess though.
That’s Turkey in the Straw.
ICs may be how they do it now, but in the 1970s? No way. Believe it or not, we had worked out ways to record and playback music long before the world went digital. I can’t find a definitive cite, but it looks like ice cream trucks mounted music boxes playing Turkey in the Straw essentially as long as there have been ice cream trucks, since about the 1950s. However, I’m don’t doubt that RealityChuck heard some with bells, or that he hasn’t heard a single one playing music in the ensuing half century. (No, I take it back. I do doubt that second part.)
There is an ice cream truck in my neighborhood that plays Korobeiniki, as heard on Tetris (the ice cream truck’s version is a bit slower).
Actual ice cream trucks rarely venture into my current neighborhood. Instead we get pushcarts with the vendor manually jingling a row of piercingly loud and high-pitched bells.
Where I used to live, ice cream trucks played “Oh, the Moon Shines Tonight on Pretty Red Wing”…
That’s pretty! What is that song? Or is it something they created specifically for Mr. Softee?
How did you post this, then? 
He can’t reply if he has no Internet connection! I’d explain how he made the OP, but my keyboard is broken.
I can’t even read this thread 
What are y’all talking about???
Been answered, but for some reason I hear them playing “Home on the Range” a lot, and also “Fur Elise”
But we have never determined why that uber creppy “HELLO!”
The Entertainer is what our local trucks play.
I should add that Mister Softee has really good softserve. One day soon when I hear it outside I’m going to breakdown and get myself a double cone with chocolate and vanilla.