If it's got 16 pins, the extra two are usually for a back light - or at least the option of a back light. The thing to do is try it with the standard Hitachi connections!.
The manufacturer's datasheet is not available on the net. Incidentally, I am not sure whether the number refers to the LCD proper or the assembled LCD board. But you can get lots of specifications and data at the follwing site:
**broken link removed**
I have myself used the JHD162A and feel that this data, particularly the instruction set should be enough for your work. Good luck
= Arun