Its DIN, and what kind of scanner is it? I know they make PS/2 to USB connections and what not, but I don't know if they'd work with a scanner.
Is there any reason you're JUST trying to find a converter? Many times these converters don't work 100%. I know my graph-link(calculator) cable won't work with my converter, it needs the actual serial connection.
For the price(and trouble) of finding a converter, you could probably find a decent scanner.