[assemble]

Dr. Pepper isn't a Coke brand, in many markets Pepsi has distribution rights for Dr. Pepper. So in those markets, they offer those products.

Pepsi wouldn't be caught dead selling Coke products in their machines. Some machines have both, but those are offered by third parties (Canteen/Vending companies) that buy in bulk from Pepsi & Coke and resell.

[munctional]

Hmm, I thought Dr. Pepper was a Coke property.

http://en.wikipedia.org/wiki/Dr._Pepper

Wiki seems to indicate that Coke manufactures it, but only does so in Europe.