The other common connector is 25 pins. That one is easy to tell, because it's the exact same size and shape as a parallel port connector. If you aren't paying attention, it will happily fit right into a computer's parallel port. Of course, it isn't all that useful like that, but I've messed up a few times with mine and put it in the parallel port by mistake. So, if it fits the parallel port, it's 25 pins. If it's a lot wider, it's the 50-pin variety.
